Auto-locking carabiner design has seen unprecedented change in the last decade, doubling in the amount of options. The newer designs are lighter, cheaper, easier to use, and much more accessible to all climbers.

In this post we cover:

  • What is an auto-locking carabiner
  • Cons
  • Pros
  • How many you might want
  • Unique examples
  • WeighMyRack’s favorites
  • How to Choose the Best (for you!)

There are two types of locking carabiners: screw gate and auto-locking. The video below compares opening a screw gate carabiner versus a standard 2-stage auto-locking carabiner.

What is an “Auto-Locking” Carabiner

An auto-locking carabiner is a carabiner that ensures added safety by locking itself shut after it’s been opened. To unlock, there is a series of steps that must be completed to open the gate. Like any locking carabiner, it should not be able to open on its own. Typically, they are also harder to open, requiring multiple different gate actions that all work to decrease the chance of them opening by accident.

This is different than screw gate carabiners, where the same mechanism to unlock is needed to lock the carabiner. It is possible for a distracted climber to forget to lock the gate – essentially turning it into a non-locking carabiner.

Screw gates had been the locking carabiner standard since their inception in the late 1890’s. Auto-lockers entered the climbing scene in the 1970’s but due to their increased weight, added price, and somewhat complex operation they were primarily used by more safety-conscious climbers. Now, gate actions are much smoother and there are many more non-traditional auto-locker options as well. The prices have also decreased slightly.

Traditional Auto-Locking Carabiners

The more traditional twist lock design consists of two main types:

  1. The standard twist lock (seen in the video at the top of this post) requires 2-operations (aka 2-stage) and opens with a twist followed by pressure on the gate. Other names brands use are 2AL, quicklock, Triact-Lock, and 2Lock.
  2. The more complicated, twist lock type requires 3-operations (3-stage), requiring a pull, a twist, and then pressure on the gate to open. Since it takes more actions to open, it’s often considered safer. Some brands call this type a triple lock, 3Lock, Locksafe, or Auto 3.
Traditional Auto Locking Carabiner Opening
the series to open a 3-stage auto-locking carabiner

Climbing gyms that provide pre-rigged GriGri’s (a belay device with assisted braking) will often come equipped with a 3-stage auto-locking carabiner, with the intention of adding as much safety as possible into the system.

Any Downsides to Auto-Locking Carabiners?

  • If you have smaller hands and the carabiner is large they can be harder to open.
  • One-handed operation will vary depending on the locking mechanism.
  • Although there are affordable auto-lockers (prices start at $11.95), generally screw gates are cheaper (starting at $8.50).
  • Although there are light auto-lockers (the weight starts at 42 grams), generally screw gates are lighter (starting at 37 grams).
  • It can be difficult to quickly identify if it is actually locked without pressing on the gate.
  • You may get in the habit of using auto-lockers and forget to lock/check your manual screw gate lockers.

Remind Me of the Upsides Again

It’s all about safety. And time. And mental assurance.

Today, there are now more auto-locking carabiners versus screwgate carabiners. In fact, over 100 new auto-locking options have become available over the last 8 years.

There are auto-lockers available that are easier and faster to use than the screw gate alternatives, that come at a reasonable price (no longer 2-3x the price of an equivalent screwgate). So it’s possible to eliminate most the downsides stated above.

How Many Auto-Lockers Do You Need?

Auto-lockers can be used anywhere a locking carabiner is desired: belay/rappel carabiner, personal anchor, power point, top rope anchors, or mid-rope connection for glacier travel.

Auto-lockers are often given/recommended to new climbers or guided climbers as it’s impossible to forget to lock it and takes intentional effort to unlock it.

The number of locking carabiners to bring has been up for debate since their inception. You can use auto-locking carabiners anywhere you would use a screw lock carabiner.

Here’s a guide for how many auto-lockers climbers could use (that is really more like how many locking carabiners does a climber need):

Zero: This means the climber prefers screw-gate locking carabiners. They may claim auto-lockers are too cumbersome, too heavy, too expensive, or hard to open one-handed. These climbers may be unaware that most of these justifications are nearly obsolete with new designs.

One: Auto-lockers are most commonly used as a belay carabiner, increasing the speed and safety at an area where a locking carabiner is opened the most. Or a mountaineer may use this as their one tie-in point to the rope during glacier travel.

Two: One as a belay carabiner and one to use as a personal anchor.

Three: There are many options such as:

  • One as a belay carabiner and two to create a top rope anchor
  • One belay carabiner, one personal anchor, and one for a following climber in guide mode
  • You could put all 3 on a pre-tied cordelette for the anchor: 2 for the bolts and 1 for the power point
  • One personal anchor and one quickdraw with 2 lockers (to be used either for an anchor, or in critical clip scenarios such as sketchy first draws and long traverses where a fall would be detrimental

Four+: Use auto-lockers anywhere and everywhere you’d like a locker. Some climbers will never use 4 lockers on a climb, and for others 4 might be the minimum they bring. Climbers that want more redundancy in the system can always find uses for another locker.

Unique Auto-Locking Carabiners

Traditional 2-stage and 3-stage auto-locking carabiners all have a very bulky and usually heavy gate. They can also be complex and/or cumbersome to use. Today, there are many alternative auto-locking options.

But there is a slight catch: With these new designs it’s more important than ever to make sure your hand can operate the release mechanism easily (think: getting it off your harness while pumped). Some of the new auto-locking carabiners will take some practice to use one-handed, but it’s totally worth the few minutes of feeling like Edward Banana Hands.

Final caveat: since these new designs required a substantial amount of R&D to develop (new molds, trials, patents, etc), they often come with a higher pricetag than their screw-gate counterparts.

Black Diamond

Update: The Magnetron is currently retired and not in production!

A 2012 debut, the Magnetron series is an auto-locking carabiner that uses magnets instead of a rotating sleeve to lock the gate. Buttons on opposite sides of the carabiner gate are squeezed at the same time to release the magnets and open the gate. Particularly small handed folks will need practice in grabbing the carabiner in an appropriate orientation to be able to reach the lock.  The mechanism is fast and easy(ish) to operate in most situations but it does require using a thumb and finger on either side of the gate. The Magnetron series is slightly heavier and significantly more expensive than their screw gate counterparts.


The intuitive Slider series of auto-lockers uses a button on the front of the gate that you press and pull down – this pull down mechanism is also in line with helping to open the gate. Some climbers have called the lock mechanism flimsy (perhaps because there is a small amount of side to side play in the button?), but WeighMyRack testers have been very impressed with how easy the mechanism is to use while climbing and found it easy to open with different hand positions and hand sizes. The Edelrid Slider series are currently favored by WeighMyRack testers for their ease of use, speed and light weight.


2015 marked the U.S. debut of Grivel’s dual-gate auto-locking carabiners. These lockers take some time and humility to get used to; with practice they can become second nature and are faster to operate than any screw gate. Once mastered, these twin gate lockers can be used just about anywhere a standard carabiner is used. Expect these auto-lockers to appear in each of the Grivel carabiner body shapes and in wire/wire, wire/solid, and solid/solid gate configurations in the future.

We have noticed combinations that include a wire gate are easier to use.


Update: This carabiner is sadly no longer produced.

The Ergo Wire is an interesting product (and typically challenging to find in North America). It was designed more for adventure parks and via ferrata as the upper lever that locks the gate when it is loaded also prevents wear on the carabiner frame – particularly helpful when the basket of the carabiner is running on steel cables.

Small handed folks will the find the ergonomics are particularly nice. Take note: This is another carabiner that can take some practice to master one-handed operation.


Update: This carabiner is no longer in production. 

A 2015 debut, the Crag HMS Slidelock is a take on the button concept. Each side of the gate has a button that needs to be depressed then pulled down for the gate to open. Like the Magnetron, the Crag HMS Slidelock uses a pinching action but then also a slight pulling action to slide the mechanism down the side of the gate. This requires the carabiner to be held fairly low which may take some time to get used to. This is also quite a large HMS so small hands will need to practice some stretching techniques.


One of the earliest designs creating an auto-locker beyond the pull-and-twist design, was the Ball-Lock. Once the button is activated the user still needs to twist the sleeve to open the gate. The twist is necessary to prevent accidental openings because the ball sits proud on the gate, compared to recessed buttons found on more recent designs such as the Magnetron and SlideLock.

What is the Best Auto-locker?

The most common question we get is, “What is the best?!” Since the best is a personal preference, we’re sharing each of our personal preferences for the best auto-locker.

Alison (small hands)

I now use auto-lockers almost exclusively – I’ve deemed screwgates slow and cumbersome. Running WeighMyRack means I get most my gear for free, so cost is not an issue. Most auto-lockers do not fit my small hand well and for this reason I favor the smallest (bonus: the lightest) auto-lockers. I love the ease of 2-stage lockers (twist, open) but don’t think that 3-stage (pull, twist, open) auto-lockers are worth the energy.

All Edelrid’s Slider carabiners. I find them incredibly fast to use and am not worried about them opening accidentally. I use the Edelrid Pure Slider (3rd lightest auto-locker at 47 grams) and HMS Strike Slider (55g) the majority of the time that I’m not testing other carabiners. When we first got these for testing I didn’t let Andreas use them because I loved them so much. The only time I didn’t love them was when climbing super long multi-pitch and my fingers were getting sore, and the locking mechanism increased my finger soreness.

I also really like Petzl’s SM’D Twist Lock and Trango’s Superfly Eco. These two models are quite similar in size, are 2-stage lockers, and I can quickly open them one-handed and they spring shut quickly. To me, they look and feel lighter than they actually are (51g and 55g).

Of all Grivel’s autlockers, I like the Plume HMS K3GH, Plume Wire Lock K3L, and Tau Wire Lock K12L best as they fit my small hands and I can fairly easily open them one-handed. Since they aren’t quite as intuitive they don’t go out as often as the above lockers.

Andreas (medium hands)

Andreas (who creates all the WeighMyRack gear videos) still uses a number of screw gates and doesn’t mind the time it takes to open/close them. For a number of screw gates he’s used a red marker on the gate to warn if the gate is not locked. I (Alison) asked Andreas his favorite auto-lockers and was surprised to learn they were exactly the same since he changes his setup much more frequently.

Edelrid Pure Slider – I use this all the time, especially for anchors or belaying in guide mode. They’re small, light, and fast.

Edelrid HMS Strike Slider / FG (with belay keeper) – Love using this for anchor master points and belaying. The new version is smaller than the original, and I have yet to determine whether they’re as good or better than the previous version.

Petzl SM’D Twist Lock – Buttery smooth, light, fast to use, I use it most for a personal anchor or with mechanical brake-assist devices.

Grivel Tau Wire Lock K12L – I use this carabiner in specific cases, most often with bolted anchors.

Andreas also lamented the retirement of the midsize Black Diamond Magnetron Vaporlock.

Jeff (large hands)

Jeff fumbles the smallest lockers and puts safety/reassurance/confidence inspiring above “ease of use.” He also doesn’t care about weight. While Alison/Andreas like the SM’D Jeff dislikes it. He finds the auto-lock TOO easy to open and the shape doesn’t fit his hand well (too small).

Grivel Plume HMS – I LOVE this thing as my main for rappelling and for belaying from above. Dual gates aren’t that tough to get used to, and its so light and quick to undo and lays really well on my Pivot. Belaying dream carabiner.

DMM Ultra-O Quicklock – Aid needs tons of lockers and you usually just get used to using whatever isn’t being used somewhere else. Except this one. This belongs to the haulbag. Its buttery smooth, locks quick, has a BIG wide opening for clipping/docking other things to the bag. Symmetry is spot on so everything just sits where you want it and doesn’t shift or ‘pop’ around. Best oval, even if it wasn’t autolocking.

Edelrid HMS Bulletproof Triple Eco – Fell in love with this one recently. Used it on a locker draw, a trad masterpoint, a toprope anchor, and belay crab all in a single day. It did all those things impressively well. The weight wasn’t noticed, but the smoothness of feed was. I’m planning on getting a few more.

How to Choose the Best Auto-Locking Carabiner

There are now over 200 auto-locking carabiners available which is a lot! So start by narrowing down on your key criteria.

Criteria To Think About

  • The amount of work involved to open (2-stage is easier to use, 3-stage is even less likely to open inadvertently)
  • Price (do you have a max budget?)
  • Shape (read this post if you need help picking between Oval, D, offset D, and Pear/HMS)
  • Size (as is true with screw-gates, auto-lockers come in most sizes from small offset D to gigantic HMS)
  • Weight (is weight a critical factor given the type of climbing you’re doing?)
  • Ergonomic Use (The combination of size and fit and the operation)

Bottom Line

If increasing safety and saving time aren’t big enough reasons to jump on the auto-locking bandwagon then stick with screw gates. The only reasons to not investigate the latest auto-lock options would be if they didn’t fit your hands, they didn’t come in your preferred carabiner shape, or they were out of your price range.

We expect auto-lockers will only increase in ease of use and will inevitably become the standard in safe climbing.

Alison Dennis

Alison Dennis

Alison (she/her) runs WeighMyRack from her 17' travel trailer. She is currently touring the US and would love if you contacted her to meet up to talk about climbing, climbing gear, or if you have any fun and/or ridiculous adventure in mind.

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We’re @weighmyrack


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