The DMM Rhino is our favorite carabiner to belay with, especially when belaying with an active assisted braking device such as a Petzl GriGri or Trango Vergo, which is why we recognize it as a Top Pick. Cross-loading of a carabiner occurs when the force is not oriented along the spine, which is engineered to be the strongest orientation, and there are seemingly countless designs that attempt to prevent this from happening. Especially when belaying, we find that the action of taking in and feeding out rope to a leader can easily allow the locker to shift, opening it up to a potential cross-loading situation. DMM's solution to this is adding a small "horn" to the outside of the spine, hence the name Rhino, that prevents belay devices from moving off of the basket and onto the spine. This solution is so simple and effective, it is impossible for us not to tout the merits of great engineering.
DMM Rhino Review
Compare prices at 3 resellers Pros: Simple design, very versatile, affordable
Cons: Doesn’t prevent rotation with an ATC style belay device, a bit heavy, can be awkward on a gear loop
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Our Analysis and Test Results
The DMM Rhino looks just like almost any other standard HMS or pear style locking carabiner, such as the Petzl Attache, but has the small little "horn" added to the outside of the spine that effectively blocks devices such as GriGris from rotating around onto the spine. Combined with a wide and flat crotch that allows the thick, flat webbing of a belay loop to sit properly, and the Rhino provides the simplest anti-crossloading solution. Since it is shaped exactly like an HMS carabiner, and doesn't have wonky features such as dual gates, or gates with strange blocking hooks, or even internal spring bars — all designed to keep the locker oriented correctly — it is more versatile for multi-pitch anchors than other belay specific carabiners. We tested a screwgate style gate, but it also comes with either a double-action auto-locking gate, or a triple-action auto-locking gate.
Of course, it is worth noting that unlike the design concepts that hold the carabiner in place on a belay loop to prevent it from cross-loading, the Rhino can still float freely. For this reason, it is less likely to prevent a cross-loaded situation when belaying with a tube-style belay device such as a Black Diamond ATC. It still works great for this purpose, but merely acts like any regular locking pear-shaped carabiner.
We love the way this carabiner works. It is designed to prevent any device with a small hole to be able to slide around onto the spine, where it can potentially cross-load. We have pointed out that the "horn" works to accomplish this on the spine, but when it comes to the gate, we also found that the locking mechanism, in our case a screw lock, also accomplishes the same feat, so a GriGri or similar device cannot slide off of the basket in either direction. GriGri's are not the only device this works with, as we noticed that our Trango Vergo belay device is also held in place, as are some devices commonly used for top-rope soloing, such as the Petzl MicroTraxion and the CAMP USA Lift Ascender. These lockers also work great to attach to regular big wall ascenders.
We found the rest of this locker's features to function at a high level as well. The gate action is very smooth and snappy, as is the screw locking gate that we tested. The basket is made of thick round stock that makes it an ideal choice for rappelling or belaying with a tube-style device, and will allow for greater longevity compared to I-beam lockers. One slight complaint we discovered is that since a GriGri can only live on the basket of the device, if we try to hang it on a gear loop of our harness, the 'biner cannot spin. When removing the locker and GriGri from this belay loop, there is therefore a slightly greater risk that the device could accidentally slip off the nose and be dropped, so slightly more attention is required.
Ease of Unlocking and Locking
We tested a screw gate version of the Rhino, but as we mentioned you can also buy double or triple action auto-locking versions. The screw gate is easy to manipulate, with friction ridges that aid your grip, especially if using gloves. If you are ice or winter climbing and have gloves on, screw gate lockers are certainly the best choice for this reason.
To go from completely locked to completely open, or vice versa, requires six half turns, or three full revolutions of the locking mechanism. This is relatively few, although not quite as quick as the only two full turns of the very similar gate found on the DMM Phantom Screwgate. That said, it is among the quickest and easiest screw gates to quickly open or closed, and having a locker that does not automatically lock is far more convenient when taking it off of the harness.
Compactness and Weight
This carabiner weighed 73g on our independent scale, which is not the heaviest locker in our review, but also roughly 20g heavier than very similarly shaped HMS style lockers.
It does not use the same I-beam construction that some other pear shaped lockers use to trim weight, which should actually mean that it will withstand more abrasive abuse without prematurely wearing through. As an HMS shaped locker, it is necessarily on the larger side, due to the fact that it needs to be able to hold a Munter-hitch, and is thus quite a bit larger than the most compact lockers we tested.
Compared to auto-locking carabiners, screw gates such as the one that we tested are not the most secure. The main concern when using a screw gate is that you remember to lock it in the first place. Anyone who has climbed their fair share of long multi-pitch routes knows that it is not that uncommon to forget to screw closed a gate once or twice during a long day. Additionally, screw gates sometimes have a propensity to become unlocked on their own over time due to repetitive micro-vibrations and gravity conspiring to allow the gate mechanism to slowly unscrew itself.
One feature that can aid in the security of a screw gate is a visual indicator, usually in the form of a red stripe, that lets you quickly ascertain that the gate is indeed locked closed. If the screw mechanism is closed, it will cover the red stripe. On the other hand, if the gate is unlocked, the red stripe will be visible, so you can quickly see whether the gate is locked, without needing to check by squeezing it. While the Mad Rock Gemini and the Petzl Attache have indicators like this, unfortunately the Rhino does not, meaning among lockers, it does not have the most secure gate you can buy.
We measured the gate clearance for this locker at 2.2cm, ranking it up there near the top of the pile with those other carabiners with the largest openings.
This is significant because lockers are designed to be used to securely attach items to other items, often ropes using knots. The larger the opening, the easier it is to slide on the multiple loops of a Munter or clove hitch without hindrance. It also makes belaying or rappelling with two ropes far easier, and in general allows for more streamlined use of the carabiner. Often times this quality of a locker is not noticeable unless the gate opening is too small, in which case it becomes immediately noticeable, for the wrong reasons. With such a large opening, the Rhino is versatile enough for use in any situation you may choose to use a locker, which is one reason we love it so much.
While it isn't the single most inexpensive locker you can buy, compared to other anti-crossloading lockers, the Rhino presents excellent value. It is less expensive than the DMM Belay Master 2, another device that accomplishes nearly the same purpose, and is less than half the price of the Petzl Freino or the Edelrid HMS Bulletproof Triple FG. If you are looking for a solid belay specific carabiner, this presents one of the best values you can find!
The DMM Rhino presents perhaps the most elegant solution to the problem of belay devices cross-loading when catching a fall, and is also one of the most affordable options for that purpose. We also like it because it lacks gadgets that can get in the way of performing other routine locking carabiner tasks, such as tying off at a multi-pitch anchor. It is very versatile, well made, and all-around a great choice for any climber.
— Andy Wellman