In reply to Paz:
> If this thing is only any good in extremis, and only recommended for metal chain / ring anchors, why would anyone plan to carry one up, let alone buy one, as opposed to simply taking a second rope?
I'm not anywhere near advocating for it, but it should be bashed on the merits. It will obviously function on any anchor that has a ring for the rappel ropes, which would be just about every anchor. It doesn't matter if the anchor material is webbing, rope, or chain.
As for why it might reasonably be carried for emergencies, it is far lighter and more compact than a second rope (even non-rated tat---you still need 60 meters of that, or actually maybe 70 meters to stay even with a single strand of 60m dynamic rope). You would plan to carry it for the same reason you might carry a first aid kit, which is to be able to cope with some type of emergency.
Like it or not, more and more climbers are going super light in an attempt to go super fast, and my guess is this will be an attractive addition to their underfilled packs.
Post edited at 03:31