March 17, 2021

Best Locking Carabiners: Buying Guide and Locking Carabiners FAQs

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by Bernice

The sole purpose of locking carabiners is to remain shut. However, once you're above ground, you don't need the stress that comes with worrying whether it will remain closed.

This is why we will review the best locking carabiners to ensure you feel safe and confident while having fun at the same time.

Some locking carabiners have screw locks, and others lock automatically, but whichever you go for, you can be sure it will not let you down. Let's get started with a list of the 5 best locking carabiners.

List of the 5 Best Locking Carabiners

#1 PETZL Attache Screw-Lock Carabiner

The PETZL Attache is extremely light, user-friendly, and easy to unscrew. It is the most user-friendly carabiner we tested. With its compact design, you would expect it to feel cramped, though it feels pretty spacious.

Distinctive Features:

  • The compact shape is purposely incorporated for several belaying utilizations like linking to a harness, among others;
  • The gate is 24mm wide and weighs 56 grams which is supremely light, and the strength stands at 22 kN;
  • The H-shaped cross-section enhances the ratio of strength to weight;
  • The wide surface makes it swift to untie and tie a munter-hitch knot;
  • The lock closure mechanism is a screw-lock system that provides decent management and reliable locking;
  • The lock indicator is also an appreciated bonus;
  • The key lock mechanism aids to avoid catching the locking carabiner on your paraphernalia by mistake.

Additionally, it has the most extensive gate clearance out of the carabiners we tested. This makes it straightforward to unclip and clip back on almost anything. It features a wide basket, while the H-shape cross-section allows for a comfy circular belay surface.

The mid-range gate tension has a satisfying snap, and the screw-gate is soft and highly functional; and it has the PETZL's s customary red coating to alert you once it's unlocked. On the other hand, this carabiner does come with a few drawbacks.

The lightweight build may translate to insignificant sacrifice on robustness, though the PETZL Attache was very sturdy throughout our tests. This locking carabiner proved to be perfect for all climbing expeditions.

When we require pre-rigged rappel and a swift top-rope arrangement, several of these locking carabiners can make great rope carabiners. The PETZL Attache has made a name for itself as a classic and the best lock climbing carabiner


  • The considerable gate clearance allows for reduced hassle;
  • Versatile and high-performing;
  • The safety stripe reveals when the gate is locked;
  • Economical price tag. 


  • Absence of auto-lock.

#2 PETZL Sm'D Locking Carabiner for Climbing

This is the best D-shaped locking carabiner we've tested. It is a lightweight full-sized locking carabiner. It has extra security and is easy to use considering its twist-locking gate.

Distinctive Features:

  • The shape allows for flexibility and warrants effectiveness in most climbing situations;
  • The 20mm wide gate is relatively light, and it has the strength that stands at 23kN;
  • The D-shape provides decent management, while the H-shaped cross-section is built to allow for an enhanced grip even when wearing gloves;
  • The two closure mechanisms - the twist-lock systems for swift opening when linking a Grigri and the screw-lock for infrequent utilization or dirty surroundings.

Whereas these types of locking carabiners are normally thought to be flexible enough for rappelling ropes and belaying, this one features a wide and flat basket than most of the ones we've tried out, guaranteeing more than enough space for two ropes to comfortably fit when rappelling.

Moreover, PETZL Sm'D Locking Carabiner works excellently when coupled with a belay gadget for setting up anchors. It was challenging to find any drawbacks with this impressive locking carabiner.

However, it is somewhat heavy though the additional weight is due to the impeccable double-action twist-lock system, which is definitely worth the extra grams. 


  • Automatically locks once closed;
  • Simple to unlock;
  • The D-shape allows for all kinds of utilization;
  • User-friendly and lightweight.


  • Somewhat costly.

#3 CAMP Photon Lock Carabiner

This stylish locking carabiner features an offset D-shape; thus, it is perfect for setting up attaches on multi-pitch climbs. Also, the CAMP Photon Lock Carabiner is ideal for attaching on one end of your anchor structure. Its versatility allows for it to be utilized for belaying.

Distinctive Features:

  • It's lightweight though this does not sacrifice durability or flexibility;
  • It has the sphere-lock closing mechanism;
  • The full-size construction is excellent for utilization when wearing gloves;
  • The optimized body build surges strength and firmness.

Its I-beam build aids to reduce the weight, and without a doubt, this is among the lightest locking carabiners you can purchase. It features a screw gate that's straightforward to close and open with just a few revolutions.

Imprinted on the gate bar is a visual indicator so you can comfortably see if the gate is entirely closed or not. However, there are several drawbacks with the CAMP Photon locking carabiner, and the most significant is that the offset D-shape is not flexible enough for rappelling.

Besides, it has a narrower gate clearance, but we didn't have a hard time integrating clove hitches or attaching them to anchor points when necessary. Lastly, the gate's spring screeches when closing and opening it, though it's most likely to annoy you than compromise your safety. 


  • Extremely lightweight;
  • The visual indicator is handy in showing whether the gate is locked or not;
  • Screwing is easy;
  • Inexpensive. 


  • The gate screeches when you open it.

#4 Black Diamond Rocklock Twistlock Carabiner

This impressive locking carabiner is ideal for belaying, considering its robust construction. Black Diamond Rocklock Twistlock Carabiner is the kind of locking carabiner that will last you a long time. Its screw gate is exceptionally soft and supremely user-friendly with marginal tension.

Distinctive Features:

  • Square hinges support the loops firmly for belaying;
  • The key-lock nose stops snagging;
  • Auto-lock twist-lock sleeve;
  • Marginally curved spine optimizes gate opening.

After some time, the springs begin to wear out though this is after taking heavy loads for a long time, which is impressive considering its price. It has a sizeable sphere-shaped stock which allows for the ropes to move through it comfortably when belaying.

The basket has enough room for hitches and knots. On the other hand, the Black Diamond Rocklock Twistlock Carabiner has one downside: it's relatively heavy. But, other than that, this is a highly versatile locking carabiner.


  • Automatically locks once closed;
  • Unlocking is easy;
  • User-friendly and versatile;
  • Its shape allows for multiple uses.


  • A bit heavy.

#5 DMM Phantom Screw Gate Carabiner

This is the way to go if you're searching for a lightweight locking carabiner. DMM Phantom Screw Gate Carabiner is among the most lightweight locking carabiner we tested. Even though it doesn't lock automatically, it has a compact build making reducing the weight easy.

Distinctive Features:

  • It's light with its weight standing at 41.5g;
  • Has strength count of 23kN;
  • The gate opening is somewhat wide at 16mm;
  • The compact design makes reducing weight easily.

We could hardly find a drawback to the DMM Phantom, lest you're attempting to rappel or belay with it as a major locker.

Indeed, it is not the type of locking carabiner you'd utilize to attach multiple loads or use for several knots and ropes, although it's incredibly supportive for almost anything else. Our testers found it to be ideal for multi-pitch climbers. 


  • It requires a bit of screwing to lock the gate; thus, it saves you time;
  • It is supremely light;
  • Soft screw lock and gate;
  • Compact build. 


  • A bit small, but some buyers said they love it because it's small and lightweight.

Best Locking Carabiners Buying Guide

1) Locking carabiners value

While climbing is fun, it is a pricey sport, especially once you start to explore multi-pitch climbs, which need a lot more gear than working out in the gym. Whereas we don't rate gear according to its value, it is an essential consideration before buying.

Locking carabiners work differently depending on their shape; thus, the most flexible ones could be viewed as the most valuable. Additionally, our testers found that lightweight locking carabiners are more valuable since the lighter they are, the higher the chances we clip them on the harness. Therefore, they will be utilized more.

The Petzl Attaché is our top pick, and it is as well highly versatile and supremely lightweight. Besides, it is pretty cheap, and it offers incredible value. The CAMP Photon is more affordable, light, and full-sized. On the other hand, the Petzl Sm'D is a high-performance locking carabiner as well.

2) Locking carabiners overall utility 

This is an evaluation of how well a locking carabiner achieves its envisioned purpose and how flexible it is. Typically, D-shaped and HMS-style pear locking carabiners are built for different intentions. However, when climbing, you can carry the smallest weight to enhance your performance; therefore, a locking carabiner that achieves more than one purpose is an excellent choice.

For this reason, we will as well consider each locking carabiner's flexibility. Among the five locking carabiners we tested, we found that the Petzl Attaché is the best combination of flexibility and functionality. It is user-friendly and spacious enough to be utilized for almost any purpose.

With its flexible pear-shaped basket and its lightweight build, it's no wonder our testers carried it with them in every adventure. This is why it is the highest-ranking HMS/Pear-style locking carabiner for rappelling.

As for D-shaped full-sized locking carabiners, the Petz Sm'D is our highest-rated when it comes to flexibility and function. According to our testers, the DMM Phantom was also quite impressive, offering plenty of versatility in various situations.

3) Ease of unlocking and locking crabiners

Among the five locking carabiners we tested, they have different locking systems; the double-action auto-locks and screw locks. By testing these closing systems multiple times, we found that some open quickly while others are challenging to open and close.

For this category, the gates that opened easily are the highest-ranking and the ones that were a bit difficult to open and close scored poorly.

4) Locking carabiners compactness and weight

Nowadays, most locking carabiners are made using an aluminum alloy that is significantly lighter than steel, and it will meet the breaking strength requirements by CE. Additionally, some rocking carabiners are made of I-beam.

The I-beam construction lets engineers eliminate additional metal while meeting testing requirements, thus lightening the locking carabiner's weight. For aluminum alloys, the construction begins to show wear much sooner, though it is significantly comfortable.

Compactness is another consideration. In most situations, you don't require a large locking carabiner that can properly attach to a munter-hitch. But having a smaller one will save you weight and consume less space on the harness.

So, why do we need climbing gear to be as compact as possible? To evaluate compactness, we measured every locking carabiner on a scale and modified the scores depending on their size and weight. Lightweight and small translated to better scores.

DMM Phantom took the first position in this category at 41 grams. The CAMP Photon was a close second weighing 43 grams. Even though compact is an excellent way to go, larger locking carabiners translate to easier ropework and increases flexibility. Lightweight and compactness cover 20 % of a locking carabiner's overall score.

5) Locking carabiners gate security

While all the locking carabiners we've reviewed will remain closed when you lock them, some climbers trust the gearless, which is why gate security is a critical consideration. Auto-locking carabiners provide impressive gate security since they automatically lock once closed.

If it is closed, you can be sure that it's locked. Screw gate lockers have a huge limitation; you need to screw them to seal them properly. The Petzl Sm'D is auto-locking, and it is quite easy to open.

The CAMP Photon and Petzl Attache have visual indicator s so that you can see whether it's unlocked, though it's covered up once locked.

6) Locking carabiners gate clearance

Locking carabiners come in different shapes and sizes, which have various sizes of gate clearance. This is the space between the nose and the gate when the gate is completely open. This is not a vital feature if you are looking to clip a single rope or sling via the locking carabiner.

However, when you're utilizing the locking carabiner as the main point and have numerous knots or ropes attached to it, this could become a problem.

Specifically, if multiple items are clipped to one compact locking carabiner, it can sometimes become challenging to open the gate and put a rope or knot.

For this reason, we frequently carry several HMS-Style spacious locking carabiners to utilize as master points on multi-pitch attaches. D-shaped locking carabiners have a less spacious gate clearance than their pear-shaped counterparts.

Regardless of not being the roomiest locking carabiner on our list, the Petzl Attache has a gate clearance of 2.6 cm, which is the largest. Taking second place is the Diamond Rocklock with a clearance of 2.5 cm. On the other hand, the DMM Phantom is last in this category with a gate clearance of 1.6 cm only.

Best Locking Carabiners FAQs

1) What is a locking carabiner?

A locking carabiner is a carabiner specifically constructed for rigging or climbing with a system that keeps the gate locked.

2) What is an auto-locking carabiner?

An auto-locking carabiner is a carabiner that guarantees safety by automatically locking itself after you open it. These locking carabiners have featured several frustrating twists to get the gate open, but it locks automatically once you release the gate.

3) How do auto-locking carabiners clips work?

Auto-locking carabiner clips need two steps to work. You open them by twisting then by applying pressure on the gate. As for closing, once the gate is released, it closes and locks automatically.

4) What is a triple locking carabiner?

A triple locking carabiner is a carabiner that features three different actions necessary to open the gate. Usually, that's sliding the metal sleeve, then winding it, and finally opening it.

5) How to use a belay locking carabiner?

To use a belay locking carabiner, clip it to your harness belay loop. However, belaying auto-locking carabiners are a better option than screw-gate carabiners because they will not open by mistake.

6) How to use a locking carabiner?

Using a locking carabiner depends on the closing system. For screw-lock closures, you need to screw the sleeve on the gate manually to lock it. As for auto-locking carabiners, they close and lock automatically.

7) How to open a locking carabiner?

Opening a locking carabiner depends on the closing mechanism. For the screw-lock gate, you open it by manually unscrewing the sleeve from the gate. As for auto-locking carabiners, you open them by twisting then by applying pressure on the gate. 


As seen, it is quite the process to determine the best locking carabiner. However, after all our tests, we have found that the PETZL Attache Screw-Lock Carabiner is the best one so far. It is lightweight, easy to use, and high-performing. 

Additionally, it has an ample gate clearance which allows for versatility. The imprinted visual indicator also reveals when the locking carabiner is unlocked. It is as well robust and durable.

Related Articles:

Our #1 Product Recommendation in the Best Locking Carabiners Category

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About the author 


Bernice often jokes that she is better at climbing than walking. With avid parents of climbing, her first encounter with the high vertical rock walls was at the age of one. Her favorite style of climbing is bouldering.

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