The Magnetron range from Black Diamond uses small magnetic pins situated either side of the gate and when closed these pins lock on a steel insert in the carabiner’s nose. When you squeeze the pins, they flick apart and you can open the gate. The pins are forced apart when open by magnetic force(opposing magnets), and when you let go, the gate shuts and the pins snap back onto the nose. You have to squeeze both pins simultaneously in order to unlock it, and this means that there is practically no chance of accidental opening.
I was as sceptical as anyone else when I first got my hands on one of these and like most people, the first thing I tried to do was make it fail. I tried wrapping the rope around the gate with no real success, covered it in mud, still no joy, and even went to the length of soaking it in water and sticking it in the freezer with still no success. I have heard of people leaving them overnight next to another strong magnet to see if this will make them fail, but no cigar. So within reason, I was pretty satisfied it was at least as safe as a traditional auto-locking biner.
Of course the next question on my mind was, is this really any better than a normal crab or is it just a gimmick? The role of any auto-locking carabiner is to safe guard against any accidental opening and this was clearly achieved. The biggest problem with standard auto-lockers is that they are normally a bit of a pain to open. You have to twist and push or something similar and this is often particularly difficult with one hand. Probably the biggest group of users of auto-locking biners are beginners and they tend to find them a real pain. The ease of opening a Magnetron is exceptional. Another thing to bear in mind is that most auto-locking biners twist to the right which is great when you’re right handed, but a total pain if you’re left handed and the Magentron is as easy either way.
Auto-locking gates are nearly always more bulky than a traditional screw gate and this can mean they are more prone to cross-loading. The Magnetron actually reduces the profile of the gate a fair bit and is a lot smoother with less edges to catch on belay loops, rope etc. This doesn’t of course mean you can’t cross-load a Magnetron, but it does seem to happen far less.
I’ve now been using the Magnetron Rocklock version for over a year and for me it is now my locking biner of choice for most situations. It is particularly great as a connector on daisy chains when aid climbing, as the gate fits nicely in your hand when used as a handle to pull up on. The Rocklock and of course the Gridlock version are perfect for belaying. Basically anywhere you need to use a locking crab that is constantly being clipped and unclipped the Magnetron really does excel.
The one draw back I can see is the price, they’re not cheap at over £20, but innovation and product development costs money and this is the case with almost all new inventions in climbing kit. So to sum up, for me, the Magnetron is probably the most user friendly and simple, yet safe auto-locking carabiner available.
The Magnetron is available as a;
Gridlock – Special belaying specific version.
Rocklock – Large, general purpose HMS version.
Vaporlock – Lightweight, general purpose HMS version.