I noticed Robi had 6 mm line with a loop in the end for the "hook". The loop had rubber tubing covering the line ... I suppose for strength and to keep the line firmly in a loop shape.

Very *soft*.

Also has the benefit of not easily coming un-hooked if not under load. I occassionally have this problem with one of my harnesses when I wear a PFD. The PFD seems to want to make the trapeze handle disengage.