Any preference? Finding one that doesn’t leave marks can sometimes be a challenge. A decent set of lined cuffs seems to mostly work OK, hands work pretty well too, but then they’re not free for other things, and I haven’t yet become tentacular! Mixed success with straps, depends on the softness and width of the material. Whilst I like the use of rope, I’m fussy about looseness and some people really mark easily with it, even with the softest ones.