12 Best Locking Carabiners

We narrowed the field of locking carabiners down to 12 top contenders and then took them out sport climbing, up multipitch trad routes, and all around the gym to name an overall winner: the Petzl Attache.

The Attache covers the most uses most effectively. Testers almost unanimously praised its craftsmanship, usability, and light weight, especially for belay or anchor use. The design is clean, versatile, and useful.

Of course, which locking ‘biner is best for you ultimately depends on your needs and usage.

Locking carabiners are essential whenever you need to make absolutely sure that the ‘biner does not fail or come undone. When belaying, anchoring, or rigging crucial systems, lockers are mandatory. At other times, they can add some useful peace of mind.

Carabiners come in a variety of shapes and sizes, and lockers are now available with a host of outlandish locking mechanisms. To find out which are best and why, take a look below.

Note: If you’re looking for non-locking ‘biners, check out our guide to the best non-locking carabiners.

Table of Contents

1. Top Pick: Petzl Attache
2. Best Anti-Crossloading: DMM Rhino
3. Best Auto-Locking: Edelrid HMS Strike Slider
4. Best Value: Black Diamond RockLock Screwgate
5. Best Lightweight: Edelrid Pure Slider

6. Reviews of the Other 7 Carabiners We Tested
7. How to Choose the Best Locking Carabiner for Your Needs
8. How We Tested
9. The Locking Carabiners Other Experts Are Recommending
10. Shout-outs

Top Pick: Petzl Attache

“Super lightweight, easy to unscrew, and easy to use,” said one tester of the Attache.

This is the Attache’s greatest trick: for how light and compact it is, it’s supremely usable.

Compact HMS ‘biners often feel cramped, but the Petzl Attache feels as spacious as any carabiner I’ve ever used. With the widest gate clearance of any carabiner we tested, it’s easy to clip and unclip on just about anything.

The basket is wide enough to hold a Munter, and the H-shape cross-section makes for a comfortable rounded belay surface. The gate tension seems to be in the mid-range of those we tested, but it has a comfortable and reassuring snap to it.

The screwgate is smooth and functional, and it includes Petzl’s traditional red coloring to let you know when it’s unlocked.

“I’m a big fan of the red,” said another tester. “It’s simple, but: ‘see red, you’re dead.’ It’s a nice visual check before you get on the climb.”

As always, there are limitations to this ‘biner. In some scenarios (with certain belay devices, for example), you’ll want a carabiner with a true round stock (like the RockLock or Rhino).

The weight savings may also mean a slight sacrifice in durability, although I’ve never known these carabiners to wear out prematurely. There’s no anti-crossloading mechanism, though as we’ll cover later, this is no great loss.

This carabiner is one that goes with me for pretty much every climbing excursion. If I need to rig a quick toprope setup, a couple of these make excellent rope ‘biners. When I’m clove-hitching into an anchor on a multipitch, the gate clearance and weight make the Attache a no-brainer. I have friends who use these as their dedicated belay carabiners, and they hold up just fine in that usage, too.

The Petzl rep at our local climbing gym referred to this carabiner as one of the brand’s defining climbing products, and it’s easy to see why. The original Attache earned its reputation as a classic, and this iteration remains one of the best on the market.

Full review: Petzl Attache

Best Anti-Crossloading: DMM Rhino

Like auto-locking mechanisms, I have very mixed feelings about anti-crossloading devices (more on this below).

Lucky for me, the DMM Rhino combines the best of both worlds: the functionality of a regular carabiner, with the streamlined usage of an anti-crossloading device (when used with a GriGri, anyway).

The distinguishing feature of the Rhino is the small namesake “horn” at the top of the carabiner’s spine.

That horn prevents most autolocking belay devices from migrating around the carabiner. When used with a regular tube-style device, cross-loading is still possible, although slightly less likely.

In practice, this was the one anti-crossloading device that I really appreciated.

It’s a joy to use with a GriGri, making the experience even more convenient and hassle-free. Testers universally appreciated this feature. Crucially, and unlike most anti-crossloading devices, this one doesn’t get in the way if you want to clip the belay device onto a gear loop between belays.

Without a device on it, the Rhino works just fine as a regular HMS ‘biner. It has a nice round stock, and it’s wide enough for versatile belay and anchor use.

I really appreciated this — if you’re using an autolocking device, the Rhino streamlines your belay life, but when you’re not, it functions just as well.

At 72g, it’s not the lightest carabiner, but it’s also not the heaviest. It’s similarly mid-range in the price department, though it’s the cheapest anti-crossloading ‘biner in our test.

DMM’s usual excellence is on display in the craftsmanship — “it’s very smooth and easy to use,” noted a tester. From what reports I could gather, durability appears to be excellent. Extra-beefy strength ratings certainly don’t hurt either.

Like the RockLock, reviewed below, this carabiner may be too bulky or heavy for some uses, If you’re a GriGri user, however, it’s an easy pick.

Best Auto-Locking: Edelrid HMS Strike Slider

This was one of the lighter HMS ‘biners in our review, and it was also one of the most usable. Like its little sibling, the Strike Slider operates using a small sliding tab as an autolocking belay device.

Testers were a little nervous about the idea of a sliding lock.

“Super easy to use, but seems almost too easy to trust,” said one.

“I just don’t want to trust the mechanics,” said another.

It’s hard to say how much of this distrust is well-placed. In practice, I never had the Strike come close to unlocking, and it’s actually fairly hard to simulate an accidental unlock.

Still, it is possible, and some testers preferred a locking mechanism that took a little more effort to undo.

The flipside is that the Strike Slider is supremely usable. “Easy action, easy to use with your thumb, and easy to use with one hand,” said a tester. In my time-trial, this carabiner was the most efficient of all. It’s a snap to use. The wide basket is nicely sized, and the construction seems compact but durable.

Especially for applications where I could keep an eye on the locking mechanism (belaying, or clove-hitching in at an anchor, for example), I really like this carabiner. It’s an auto-locker that doesn’t get in the way, and the efficiency and usability are excellent.

Edelrid also makes a version of this carabiner with an anti-crossloading gate (as well as a screwgate version), and I was able to briefly get my hands on one. I found it more usable than either the GridLock or the Gatekeeper, and it could be a good option if you require a safeguard.

Best Value: Black Diamond RockLock Screwgate

You’ve probably already seen this carabiner — it might be the most common in belay and gym use, and there are several good reasons why.

First of all, the RockLock is burly.

“It’s just tough and durable,” said one tester. “It’s a good beat-the-****-out-of-it-and-not-have-to-worry ‘biner.”

The large, round stock on the RockLock means that ropes feed smoothly on any belay device, and the spacious basket allows plenty of room for knots or hitches.

The screwgate is easy to use, if not particularly smooth. The gate tension is on the lighter end, and some friends of mine have reported that over long periods of heavy use the spring can start to wear out. Overall, however, durability seems to be quite good.

And best of all, you get all that metal for an affordable price. This is about as cheap as it gets for a full HMS carabiner, and it’s almost certainly the best budget buy around.

That’s not to say there aren’t a few drawbacks.

Chief among them is the weight — at 85g, this carabiner is more than twice as heavy as the lightest in our test. This isn’t always an issue. “I usually don’t do anything where I’d notice the difference,” said one tester. If you’re trying to stay light, however, there are better options. The RockLock is also too chunky for some applications (like anchoring into a bolt).

But for all-around use as a belay ‘biner, especially if you’re racking up miles at the gym, there’s no reason not to get the RockLock.

It’s reliable, durable, and affordable. And at its price you may as well get two.

Full review: Black Diamond RockLock Screwgate

Best Lightweight: Edelrid Pure Slider

At a measly 42g, this carabiner tied with the DMM Phantom for the lightest in our test.

It also features an unconventional locking mechanism — a small sliding tab that automatically locks when not in use.

On both this carabiner and it’s larger HMS brother, testers were a little nervous to trust the mechanism at first. “It seems like it’d be pretty easy to open by accident,” said one.

This is a valid concern, but in practice I didn’t see it carried out.

It’s certainly possible for the tab to open if pressed in exactly the right way, but the same is true of most lockers. I’ve seen screwgates come unlocked just from rubbing against rock.

In most scenarios where you’d be using this carabiner — hanging a belay device in guide mode or anchoring into a bolt, for example — you’ll be right there to keep an eye on things anyway.

What the slider does give you is total ease-of-use. It’s a snap to open one-handed, and the autolocking is convenient and efficient.

In most cases, I prefer manual locking mechanisms because autolockers are too much of a pain to unlock every time, but this mechanism is the exception. In my time-trial test, this carabiner was second only to its elder sibling. It didn’t seem to get clogged or stiff from time outdoors, and it’s still usable with climbing gloves on. The spring tension is reassuringly high, and the action is smooth and snappy.

Where you want a little extra piece of mind on protection, this ‘biner is also surprisingly useful. With a little practice, you can clip it almost as easily as a regular non-locker. If you’re about to run it out past a piece that cannot fail, the Pure eliminates almost any chance of unclipping.

In the end, it was these slight usability perks that gave the Pure the edge over the DMM Phantom for our title of Best Lightweight Locking Carabiner, although both are excellent.

The downside is that the Pure Slider is on the expensive side for a small locker. Luckily, Edelrid also makes a screwgate version, the Edelrid Pure Screw, which retails for a bit less and would make an excellent budget pick.

When you’re filling out your rack with general-use lockers, weight will make a difference, and the Pure Slider is a versatile (if unconventional) pick.

Reviews of the Other 7 Carabiners We Tested

There were plenty of other good (and bad) carabiners in our review. Read on for the details and best uses of each.

DMM Phantom Screwgate

This is another super-lightweight ‘biner, weighing just 42g. It’s also the smallest locker in our test.

I was mostly impressed with how usable the Phantom remains despite its size. I almost never noticed how small it was except to admire its lightness.

The size does limit usability slightly. As with most asymmetric-Ds, this isn’t a carabiner you’d want as your regular belay ‘biner, and it’s too small to hold big knots or hitches.

Still, for most applications where you’d want a carabiner of this shape, the Phantom keeps up with the competition just fine, and generally for less bulk and weight.

DMM tends to make polished pieces of gear, and the Phantom is no exception. The screwgate is very smooth, and the whole design is reassuringly clean. You hardly notice it on your harness or tucked away in a pack.

The Edelrid Pure Slider ultimately edged it out with a little more versatility and size for the weight, but for the gram-counters among us, the Phantom is still a great choice.

Petzl Spirit Screw-Lock

Based on the incredibly popular Spirit carabiner, this is another lightweight offering from Petzl.

It features typically excellent Petzl craftsmanship, complete with red strip to alert you when the ‘biner is unlocked. The screwgate is just as good as the one on the Attache, and the action is similarly smooth.

The Spirit is a scant 3g heavier than the Pure Slider and Phantom, and it offers a slightly wider gate opening than either. This is a carabiner that functions pretty much as you’d expect it to, and that’s a good thing. It’s reliable, well-designed, and easy to use.

The beefed up metal near the top of the spine may provide a slight durability advantage as well, although it’s hard to say without years of use.

This carabiner does have the most aggressive angle at the top of the spine, which gives it a different feel than most. Still, as an all-around pick, the Spirit Screw-Lock is predictably reliable and high-quality.

Black Diamond VaporLock Screwgate

This was the lightest and smallest of the HMS-shaped carabiners in our test, and it’s still a solid performer.

“It’s your standard lightweight ‘biner,” said one tester.

In most respects it’s not exceptional, but it’s functional for almost everything.

It’s usable (though not perfect) as a belay or anchor ‘biner, but it’s light and small enough for use  in other applications as well.

One tester did report that the screwgate occasionally got stuck. It’s hard to say if this is a general problem. In my experience, though, Black Diamond screwgates can get a little finicky over time.

Overall, the VaporLock would rarely be my first choice for a given use, but it’s capable at almost everything.

For a true all-arounder, or for the absolute lightest pear-shape, it’s worth a look.

Black Diamond Positron Screwgate

The Positron is reliable and user-friendly. It has a relatively wide gate clearance (due to a slightly curved spine), and it’s the largest of the asymmetric-Ds that we tested.

For applications where you would want a carabiner of this shape, the Positron does just fine.

The gate tension is on the lighter side, and the screwgate isn’t quite as smooth as the Petzl or DMM offerings. It’s also on the heavier end for a small carabiner.

Still, the Positron is what you expect from Black Diamond: simple and functional.

As a bonus, it’s also very cheap — as a budget pick for this shape, the Positron is a reasonable choice.

Mad Rock Ultra-Tech Screw

A budget offering from Mad Rock, this carabiner performed reasonably well in most circumstances. Along with the Black Diamond Positron Screwgate, this ‘biner was the heaviest asymmetric D in our test, but somehow it felt especially chunky.

It’s hard to pin down exactly why, but I found myself getting hung up with the Mad Rock more than I did with the other ‘biners.

The screwgate is nothing special, but it’s reasonably smooth, and the gate tension is neither light nor heavy.

Still, something about the construction felt awkward, and I found myself fumbling more than I expected. The shape is fairly typical, but the outline of the Ultra-Tech’s basket is flatter than most, which made feeding a rope just a little less smooth.

It was these usability and functionality quirks that ultimately cost the Mad Rock in our rankings.

If you’re looking for the cheapest option, the Ultra-Tech will get the job done, but there are better options available.

Black Diamond GridLock Magnetron

This carabiner features both an unconventional design and an unusual locking mechanism. I have my doubts about both.

Although, in the right application, the Gridlock could be a good option.

Black Diamond’s Magnetron system has been around for a little while now, and it’s certainly slick. A small magnet at the top of the gate attracts two flaps on either side that lock the gate in place.

With a little practice, it’s not too hard to undo and open (even with one hand), although it’s not as easy as Edelrid’s slider system. It can also be difficult to operate with gloves on.

For me, this mechanism wasn’t quite smooth enough to forgive its inconvenience, especially when repeatedly opening the carabiner.

Adding to the trouble is that this carabiner requires multiple openings due to its anti-crossloading mechanism.

To secure the belay loop or device, a small tab sticks out from the base of the gate and crosses the opening. Once set up, this is a nifty system — it effectively secures and orients the ‘biner. Getting it on and off can be a bit of a pain, though, especially when you’re in a hurry.

This carabiner was actually the worst of all in the time-trial, and most testers didn’t appreciate the process it took to get everything set up.

“It’s too irritating and too many steps to get it fully loaded,” said one. “If I’m in a pinch, it’s gonna trip me up.”

Another tester found that when trying to remove the carabiner, it was easy to get the tab caught on the belay loop, making the ‘biner difficult to open.

Additionally, this ‘biner (along with the Gatekeeper, reviewed below) is pretty much a one-trick pony. It can belay, and it could probably fit a Munter if necessary, but that’s about it.

It’s far too inconvenient to take up a multipitch climb, and it’s not even great at carrying a device on a gear loop. Ultimately, all these annoyances cost the Gridlock quite a few points.

That said, if you’re looking for an extremely safe carabiner to be your dedicated belay ‘biner (especially in the gym), I could see the Gridlock being a possibility. It’s an effective anti-crossloading safeguard, and with time and a lot of practice it’s possible that use would get easier and more efficient.

Still, I can’t say I recommend it.

Full review: Black Diamond GridLock Magnetron

Metolius Gatekeeper

This carabiner was, unfortunately, almost universally disliked.

Chief among the reasons was a screwgate that takes approximately a decade to open or close. Where most screwgates allow for a little spin, the Gatekeeper requires that every twist be done manually.

There are far more threads than seem strictly necessary, and the end result is a ‘biner that takes noticeably longer to open or close. When you’re using it as a belay carabiner (as you must, with this one), this adds up.

Adding to the difficulties is the anti-crossloading mechanism. This carabiner features a wiregate attached partway down the spine, which is spring-loaded to cover the gap.

Once set up, it’s an effective guard. Unfortunately, getting it set up is, again, a bit of a pain.

“It’s not attached to the gate, so it’s a whole separate mechanism,” said one tester. “It’s more of a process ‘biner than it should be.” The wiregate also feels unnecessarily stiff, which doesn’t make it any easier to get the Gatekeeper on or off.

Like the Rhino, the Gatekeeper features a wider section of metal at the top of the spine to prevent the migration of autolocking belay devices. Unlike the Rhino, belaying is all the Gatekeeper can ever do.

It’s hopeless at anything else, and in my opinion, not that great as a belay ‘biner. It does the job, but it’s not particularly usable or useful. I’d advise that you look elsewhere.

Summary

Here are the best locking carabiners:

• Petzl Attache
• DMM Rhino
• Edelrid HMS Strike Slider
• Black Diamond RockLock Screwgate
• Edelrid Pure Slider
• DMM Phantom Screwgate
• Petzl Spirit Screw-Lock
• Black Diamond VaporLock Screwgate
• Black Diamond Positron Screwgate
• Mad Rock Ultra-Tech Screw
• Black Diamond GridLock Magnetron
• Metolius Gatekeeper

How to Choose the Best Locking Carabiner for Your Needs

Locking carabiners come in different shapes, sizes, and types, and different circumstances can call for different ‘biners. The more you expand your climbing skills, the more likely it is that you’ll want a few different lockers.

Here are a few of the relevant concerns.

Shape

There are two basic shapes for modern lockers:

• HMS (or pear-shaped)
• Asymmetric (or offset) D-shaped

We tested 7 of the former and 5 of the latter.

HMS ‘biners tend to make the best belay carabiners. Their wide baskets make for easy setup and smooth feeding, and the width is also necessary if you ever have to belay off a Munter hitch. This is actually where the acronym “HMS” comes from — the German word for a Munter is (with typical German bombast): “Halbmastwurfsicherung.”

These carabiners are also good for applications like clove-hitching into the master point of an anchor.

Asymmetric D-shaped carabiners tend to be lighter and less bulky than their larger counterparts. This makes them less than ideal for many belay applications, in which brake strands can easily get pinched by narrow designs.

But say you’re going in direct to a couple bolts at the top of a sport climb, in preparation to clean. You’ll want something light enough to be out of the way and narrow enough to fit easily on a bolt hanger. For applications like this, or for something like hanging a belay device in guide mode, asymmetric Ds excel.

There are other shapes as well (ovals and symmetric Ds), but in most climbing applications you won’t need them.

Size & Weight

Just like the shape, the size of a locking ‘biner can sometimes dictate its best uses.

A big, burly HMS ‘biner like the RockLock will make an excellent everyday belay carabiner, while a smaller lightweight like the VaporLock is best reserved for more occasional use. Still, compact ‘biners like the Attache prove that smaller HMS lockers can be just as capable as larger ones.

In some belay devices (especially in guide mode or on rappel), it helps to use a carabiner with a round stock. In those cases, you’ll want to snag something like the RockLock or Rhino.

If you’re a gram-counting alpinist (or you just want ‘biners that won’t take up a lot of space), there are some very functional lightweight lockers to choose from. The Pure Slider, Phantom Screwgate, and Spirit Screw-Lock are all good options.

Small, lightweight ‘biners are often slightly less durable than larger or heavier ones, but the difference generally isn’t huge, and the sacrifice can be worthwhile.

Autolocking vs. Non-autolocking

In general, I much prefer manually locking carabiners to autolocking.

I always try to double-check systems involving a locking carabiner anyway, which means that I shouldn’t be forgetting to lock or check my carabiner.

The great advantage of non-autolocking ‘biners is that you can leave them unlocked, which saves you time, thought, and effort when you’re opening and closing them. When setting up a belay device in guide mode, for instance, it’s far more convenient and efficient to have standard carabiners.

I do understand wanting an extra safety margin, and especially in the gym I don’t mind having my carabiner lock on its own. Still, for the majority of circumstances, I find a screwgate much less of a hassle.

Most of the carabiners in this review are also made in an autolocking version. If that’s your style, feel free.

The exception to these reservations was the Edelrid Slider ‘biners. I like Edelrid’s system — it’s so easy to use that it eliminates almost all the inconvenience of having to unlock the carabiner every time you open it.

As discussed above, testers had some concerns about the safety of the carabiners, but in most applications I find them very reliable. I believe Mammut makes a similar system, though I haven’t gotten the chance to test it.

The other unconventional locking mechanism we tested was Black Diamond’s Magnetron. I was pretty ambivalent about this mechanism. It’s a little easier to use than a standard autolocker, but not easy enough to get rid of the inconvenience factor. It’s a little finicky sometimes, and it requires just a little more thought and effort (especially with gloves on). It’s also substantially more expensive.

OutdoorGearLab pointed out that Magnetrons can get stuck in the cold (although screwgates will sometimes freeze shut, too). In general, I would still prefer a screwgate to Black Diamond’s system, as nifty as it is.

The RockLock and VaporLock are both available with the Magnetron system, so if you prefer an autolocker, they could be worth a look.

Anti-crossloading Mechanisms

This is another improvement on carabiners that I generally don’t like.

I do understand the safety concerns — crossloading a ‘biner severely diminishes it’s effective strength, which is not something to be taken lightly.

In practice, however, I’ve almost never encountered crossloading as much more than an annoyance. The lateral strength ratings on carabiners (generally in the neighborhood of 7-9 kN) is still far greater than you would ever expect to approach on a belay.

The downside is that anti-crossloading mechanisms are generally awkward to set up and undo. They require an extra step in each direction, and they frequently decrease a carabiner’s versatility in other applications.

For dedicated belay ‘biners, anti-crossloading systems can streamline usability and add a little bit of safety margin. If those concerns are important for you, the GridLock is worth a look, as is the Edelrid Strike FG or the DMM Belay Master.

In most cases, however, I’d say that spending the extra cash isn’t necessary.

The exception to these concerns is the DMM Rhino, which works great as a regular ‘biner as well as being an anti-crossloader for autolocking devices. If you use a GriGri 2 or GriGri + (or other similar device), check it out.

How We Tested

To test these carabiners, I took them out in all the relevant climbing venues available to me.

I took them all out for a day of sport climbing and had testers belay with each in turn. I took them out for a day of multipitch climbing and used them for things like clove hitches and anchor-building. I belayed with all of them in the gym. I put on gloves and practiced opening and closing them.

And for my final test, I simulated a series of steps that a climber would go through to put someone on and off belay, and then timed myself using each ‘biner. I did multiple trials, averaged the times, and included the results as part of scoring.

I scored the ‘biners based on three major categories.

1. Functionality

How well does each carabiner do what it ought to do? How many different tasks can it accomplish? How well does its design suit its function? How smoothly does it fit into its role?

2. Ease of Use

How easy is the carabiner to lock and unlock? How easy is it to clip? How efficient is it when setting up or taking down? Do its features make it easier or harder for me to use it safely and efficiently? How intuitive and easy is it to use?

3. Portability

Does the carabiner get in the way of other things when clipped to a harness? Can it effectively carry other gear? How light or heavy is it? Do I mind taking it with me for various applications?

The Locking Carabiners Other Experts Are Recommending

OutdoorGearLab didn’t test the same carabiners we did, but they came up with similar results. They also highly recommend the Petzl Attache, along with the Edelrid Pure (Screw) and the Black Diamond RockLock.

The folks over at Moja Gear are also fans of the Positron, but they don’t mind BD’s Magnetron system as much as I do. They recommend it (especially on the RockLock) as the autolocking mechanism of choice.

These are all solid bets. Most of these carabiners are fairly good — you’ll notice that most of our scores were above 80. Almost all of them will get the job done, and even the poor ones lose marks mostly for inconvenience (looking at you, Gatekeeper).

Find the best one for your applications and then start refining. You’ll quickly discover what you like and what you don’t.

Shout-outs

Special thanks to the climbers (Jess, Nate, and Sam) who helped me test, gave me their opinions, and put up with me talking about locking carabiners all the time.

Thanks also to Salt Pump Climbing Co. for letting me test and take pictures in their facility.