|I picked up one of these to try out as my new belay karabiner. I've been using an Edelrid belay biner recently with a captive wiregate that goes around the belay loop on my harness, and got to like that feature very much. I don't really have concerns about cross-loading when belaying from my harness, but I do like the way the gate holds the karabiner in the correct orientation all the time - I find that there is less fuss when orienting the ATC correctly, and I never feed the ropes upside down any more. So when I sold that biner (part of a set with a Megajul) I went looking for another biner with a captive loop, and found this little work of art:
Grivel's twin-gate technology is covered in a couple of reviews on MP, but I haven't seen it in person, and haven't seen this belay biner before. In the hand the biner oozes quality - a beautiful finish, smooth action, and clever design. The weight is kept down by I-beam construction for the most part, but the working area is a nice wide-radius rounded shape, with plenty of space for munter or clove hitches. The belay loop attachment area is squared off so that belay loops sit square and snug, and the wire keeper gate holds it firmly in position. Not only does it stay in position, but the nature of the keeper means that even when the gate is open (putting someone on/off belay) the biner is firmly attached and isn't going anywhere.
I wasn't specifically looking for a twin-gate, but the advantages seemed obvious - if the gates are closed, they are locked, no need to check. How many times have I double & triple checked my screwgate, sometimes nervously while my climber is on the verge of falling? I like the idea of never having to even consider it again.
So how is it in practice? "Practise" is the key word there.... Initially I found the twin gate awkward to use. The recommended way of opening is shown below:
The golden outer gate has a ridge on the side that protrudes beyond the black inner gate, allowing you to use the side of your finger or thumb to open it. It took me a little while to realise that when clipping the karabiner onto the belay loop or keeper loop on the harness, you don't need to open both gates - simply open the outer gate, and push the biner into place, the inner gate opens by itself. Then once it is on the belay loop, simply pull it outwards and the wire keeper opens and closes around the belay loop - simples. It took me a bit longer to work out how to easily get the ATC loaded and unloaded without removing the wire keeper from the biner. And taking the biner off the harness and racking it on a belay loop was positively fiddly and took 2 hands initially. I found it annoying when gym climbing and frequently swapping from belay to lead & back, and was concerned that on a multipitch, I'd be more at risk of dropping my ATC.
But then I found Grivel's videos, where the biner is demonstrated by Stevie Haston (the Clint Eastwood of the climbing world) who displayed gunslinger-slick moves in clipping, unclipping and re-clipping the biner in every conceivable circumstance. I too would like to be as cool as Stevie Haston, and spent some time in front of a mirror practicing my facial expressions (primarily a tiny, wry smile, as if to say yes, I do find this a little embarrassing but the pay is good). I also practiced the moves, and it has become much easier. Some actions are much quicker and easier than a regular screwgate, where 1-handed operation would be very difficult. Other actions will take a bit of practise, but I think after a few more sessions it will be second nature.
And I'm happy to put a little effort into changing my habits, as I really like the biner itself, and the little extra peace of mind in knowing that the gate is always secure. I tried all sorts of things to find a way to defeat the twin-gate, but can think of no real-world circumstance where a rope can get out of the biner without deliberate intervention by the belayer.
Pro: a very nicely made biner, very usable, all regular features of a good belay biner in terms of strength, good gate opening width, nice rounded working surface - plus excellent shaped belay loop attachment point, wire keeper gate for the belay loop, and innovative twin gate security. You get to look like Stevie Haston.
Con: some effort involved to learn new techniques for clipping / unclipping.
Overall - I like it, and appreciate the additional safety and usability. I wouldn't necessarily advocate going out and changing your current belay biner - but if you are in the market for a new one, I'd give this a try, I think the twin gate is fantastic in this application