The Black Diamond GridLock Magnetron is a belay specific locker that uses magnetic technology in the gate to create an auto-locking system that is quite a bit different than most standard twist locks. In order to open the gate, you must squeeze two lever arms, one on each side of the gate, which releases the magnetic grip with the nose. The gate also features a curved extension bar off the bottom that combines with a unique shape to trap the belay loop of the harness in place, preventing potential cross-loading. While this carabiner is effective for the purpose it is designed for, we found it to be laborious to use, and honestly felt a bit exasperated having to open and close the gate so many times to fiddle the locker onto our belay loop, or to add the belay device, especially during long sport climbing sessions or at the gym. This is one case where the convenience of a screw gate, which doesn't automatically lock whenever it's shut, may be worth the trade-offs, and BD does make the GridLock Screwgate for those interested.
Black Diamond GridLock Magnetron Review
Compare prices at 3 resellers Pros: Magnetron technology is securely auto-locking, prevents cross-loading while belaying
Cons: Very fiddly and time consuming, hard to use with gloves, heavy, instructions for use with active assist braking devices not intuitive
Manufacturer: Black Diamond Equipment
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Our Analysis and Test Results
While the GridLock Magnetron is one of the most popular belay lockers that we see at the crags and in the gym, our testing reveals that it is laborious to use and indeed is often used incorrectly, which we are even guilty of before being clued in by in-depth internet research. The internal bar attached to the gate requires the gate to be opened in order to slide the belay loop into the correct position in the crotch of the locker, if you are belaying with an ATC. However, if you are belaying with a GriGri or other similar device, you are supposed to load it into the small end, trapped by the internal bar, with the large end attached to your belay loop. Not only is this annoying and difficult to do, but is completely counter-intuitive, to the point where we have never actually seen someone using this locker correctly in this way at the crag. Not convinced, check out the screenshot below of Black Diamond's visual instructions for this locker, taken directly from their website.
While we find the Black Diamond Vaporlock Magnetron to be one of the best auto-locking pear shaped 'biners you can buy, in the case of the GridLock we actually think the magnets are partly responsible for the constant difficulty in using this locker, and would instead recommend the Black Diamond GridLock Screwgate, which won't be quite as secure with the gate closure, but will be far easier to use. Regardless, we would highly recommend checking out other belay specific carabiners, such as the DMM Rhino or Edelrid HMS Bulletproof Triple FG, before buying this one.
In terms of overall utility, we find this locker to be one of the lowest scorers, and were the most frequently frustrated while using it, a poor attribute of any product no matter what its purpose. Since the interior lever bar is attached directly to the gate, in order to move it, one must also open the gate. This requires a minimum of two gate openings any time one wants to either put someone on belay or take them off belay, which simply shouldn't be necessary. This action is compounded by the fact that the Magnetron gate auto-locks every time it snaps closed, requiring you to squeeze the triggers to open it every time. The fact that there is a different method of loading a GriGri or other similar device compared to an ATC, and that it is counter-intuitive, is another knock against the design. The internal bar also prevents this locker from being a good choice for other applications, such as building multi-pitch anchors, and the magnetron technology is hard to manipulate with gloves on in the winter. All of these facts contribute to it being one of the least versatile lockers that we tested, and receiving a correspondingly low score.
Ease of Unlocking and Locking
To lock this carabiner is as simple as can be, the magnetic technology automatically causes it to lock the moment the gate snaps closed. To unlock it requires pinching the two metal levers on each side of the gate, which can be hard with gloves on. While this technology works well with a simple pear shaped locker like the BD Vaporlock Magnetron, it actually makes this locker more difficult to manage, because of the aforementioned lever arm making it difficult to open the gate at times. A low scorer in this department.
Compactness and Weight
We weighed this locker at 82g on our independent scale, which ranks it up there near the top in terms of heaviest carabiners. Combined with its heavy weight is the shape of the design, which is slightly figure-eight shaped with one end larger and one end smaller. This makes it bigger and less compact than other lockers. These two factors once again make it a low scorer for this metric.
The Magnetron gate greatly adds to the security of this locking carabiner, which is the main reason people would be inclined to buy it. When the spring-loaded gate snaps closed, it automatically locks, and the fact that to unlock it requires pinching a specific place on both sides of the gate makes it extremely unlikely that it would accidentally open on its own. While we think the GridLock Screwgate would be a much easier version of this locker to use, we concede that the Magnetron is more secure. The only thing you should watch for is that ice or ferrous dirt can clog the magnets, thereby inhibiting the ability for it to lock closed, so a visual inspection now and again is still a good idea.
We measured the gate clearance of this locker at 2.4 cm, making it among the largest that we tested. This is great for getting belay devices or knots on or off the nose of the carabiner, but this also comes with a catch. The clearance of the internal bar is much smaller. Since it is attached to the gate, it can easily inhibit the gate from opening if a belay loop or GriGri isn't positioned correctly within its small ring.
One of the more expensive lockers in this review, it costs more than double the price of numerous other lockers that are easy to belay with. Much of the price is due to the Magnetron technology — the Screwgate version is much cheaper, nearly half the price, making it a far better value. Since we don't think it performs well compared to the competition and isn't super cheap, we can't call the GridLock a great value.
The Black Diamond GridLock Magnetron is a belay specific carabiner designed to prevent the possibility of cross-loading when catching a fall. We have seen many wildly different designs that attempt to solve this problem, but unfortunately Black Diamond's is the most annoying to use. Manipulating the belay carabiner repeatedly is an inherent part of belaying while climbing, and since this design makes this a challenging task compared to others, it is not by any means the first one that we would recommend buying.
— Andy Wellman