The Black Diamond RockLock Twistlock is a large, HMS/pear shaped locker that is easy to use and handle and provides solid gate security with its auto-locking, double-action gate mechanism. Made of thick, round stock, this biner has a large, round basket that works great for anything you could possibly need to use it for, and is effective at cutting down on inherent friction in a belay system. The only downsides are its rather large size (also a plus), and its heavy weight. This versatile locker works great for belaying with a GriGri or ATC, is ideal for rappelling with two ropes, and is also useful as a master point of an anchor or for top-roping, although it can also be used for nearly any other purpose as well.
Black Diamond RockLock Twistlock Review
Compare prices at 3 resellers Pros: Versatile, great for use with double ropes and belaying, auto-locking gate mechanism, wide gate opening
Cons: Heavy and bulky
Manufacturer: Black Diamond
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Our Analysis and Test Results
The RockLock Twistlock is an HMS or pear style locker, which means it is designed to be compatible with a Munter hitch. While people rarely belay using a Munter hitch these days, it can be very helpful to know how to in case you drop your belay or rappel device, and it requires a large, rounded basket for optimal function. The round stock of this carabiner helps reduce friction, while also improving durability and hopefully longevity, but has the notable downside of making it quite heavy. We tested the Twistlock version, which features a double-action auto-locking gate that is easy to use with only one hand. The RockLock also comes in a Screwgate option that is a fair bit cheaper, although neither is expensive overall compared to the competition.
HMS/pear shaped lockers such as this one can be used for literally any purpose you will encounter while climbing, and are therefore the most versatile of all lockers. Their primary purpose, however, is as a belay/rappel biner. The wide, rounded, basket made of round stock is designed to accommodate a Munter hitch, which it does well. The side effect of this design is that it easily accommodates two ropes while rappelling without pinching the ropes and increasing friction, like what happens if you try to rappel using an offset-D shaped locker. The reduced friction is ideal for any sort of belaying scenario, including when using an ATC in guide mode and belaying off the anchor. In this case, we prefer to use a round HMS locker like this one to trap the rope, and use a smaller, lighter offset-D for attaching the device to the anchor.
That said, for use primarily while belaying, the RockLock does not have the anti-crossloading features found on many other belay specific lockers in this review. The crotch is designed extra wide and flat so that a belay loop sits nicely in place, but there is nothing to actually hold it in place. We found that the RockLock works well as a master point of an anchor or for attaching ourselves with a personal tether, although may be a bit heavy and large for this last purpose.
Ease of Unlocking and Locking
The double-action Twistlock feature means that one has to perform two actions to open the gate: twist the locking mechanism a half twist to line up the openings properly, and then pull the gate open. In general, this method is fairly easy compared to screwgate lockers, and certainly takes less time. Opening the gate can be performed with one hand, although the gate twists to the left, so we found it a bit easier with our right hand than left hand. The only downside is that you must perform this action every single time you want to open the gate, which can be a little bit of a pain depending on how often you use it. The upside is that the gate automatically locks itself every time it closes, and this locking is based upon spring action, so no effort is required.
Compactness and Weight
On our independent scale the RockLock Twistlock came in at a weight of 93g, which translates out to roughly 3.3 ounces. This made it the single heaviest locker in our entire review, heavier even than all of the anti-crossloading lockers, most of which include added features that contribute to a higher weight. Considering the round stock construction and the overly large size, it's easy to see how this locker ended up being so heavy, but this is also a fairly serious downside that would convince us not to consider carrying more than one of them at the most.
Because of its spring-loaded, double-action locking mechanism that snaps closed and locked the moment it's released, this is one very secure locker. We find it to be much more secure than screwgates because one never needs to remember to lock it — locking just happens automatically. Similarly, there is no need for a visual indicator to assist with knowing if its locked or not, because it's locked if it's closed. While a triple-action locking gate might be even more secure, we have a hard time imagining scenarios where this gate would open on its own, causing an accident.
We measured the gate clearance on this locker at 2.5cm, which is very nearly the largest of any we measured. A wide opening accommodates getting knots on and off the basket and over the nose, which is pretty easy regardless of what type of knots. With a basket so large, we found that it's not at all unreasonable to fit two knots on this locker, or two items clipped to it.
The retail price for this locker is a bit higher than your average screwgate locker, and indeed, if you purchase the screwgate version instead of the twistlock version you can expect to save over 30%. However, it is far cheaper than most of the anti-crossloading, belay specific lockers that we tested, and remains more versatile than most of those due to not having the added special features that prevent its use for purposes other than belaying. As one of the higher scorers in our overall testing, with the only notable downside being the weight, we think you will find good value here.
The Black Diamond RockLock Twistlock is a large HMS style locker that is versatile for nearly any purpose, but specializes in belaying and rappelling. Because it can be used for so many different things, and is also very secure due to its auto-locking gate, we think it makes for an excellent first locker, and is useful for nearly everyone. Most climbers should find no reason to need more than one, though, as it's likely more practical to round out the rest of the rack with lighter and smaller offset-Ds.
— Andy Wellman