In reply to kingjam:
if you thread it (basket hitch not larks foot) they are pretty strong.
see the dmm video/page : 9..12kn
I use it if there is a danger of a krab being cross loaded over an edge. Prefer fatter (10/11/12mm) sling to skinny 6mm dyneema , but dmm results (note with new kit) are still promising.
BD dont use a thing extendable sling as a big fall will deform the loop wire
(don't think they broke any) and repeated falls may break it. its on their site somewhere!