In reply to escalator:
> (In reply to davidbeynon)
>
> I've used it quite a lot, and not had one slip. However, you need to pay particular attention to ensuring that the karabiners are lying right, and wont move. I have found that some karabiners don't lend themselves to it very well. Use what you have and see which work best.
I find it works best on krabs with a fairly tight bend. I use one for the foot sling when prussicing as I find it easy to pull up the sling if I keep the dead rope hanging over my shoulder.