Love my wrist & ankle cuffs! I sleep in them quite often, and they never leave a mark. During rough play, they have held up just fine. My BF would often spread-eagle me to the bed using these cuffs with a bit of chain, and I NEVER had the sensation that they wouldn't hold me, even when I struggle. And I LOVE to struggle. ALOT! These are a GREAT investment for any bondage enthusiast!