WARNING: These are NOT 'play' nipple clamps, but truly the REAL DEAL!! I have used nipple clamps before, and have had some pretty hard core ones too. These are definitely on the level of hardcore! These heavy, metal butterfly clamps are very 'bondage-esque' and will definitely grab on and not let go - even with the most severe pulling! These clamps are simply to use: Squeeze the opposite end from the clamp, attach to nipples, let go and .....scream, moan, sigh......it is all dependent on your pain tolerance. The clamps have little, rubber pads to 'protect' your nipples - but - the pads have little nubbies on them for a no-slip grip. Many might find this very uncomfortable. My hubby and I used these clamps last night as part of 'Bondage Wednesday' - and I have to say, while they were definitely painful, I found it a satisfying type pain. Once placed on my nipples, the heft of the connecting chain pulled them down slightly, causing a delightfully painful pulling sensation. When my hubby pulled on them during sex I about lost it. The best part was when my nipples were released from their bondage and my hubby 'kissed them' to make it better! The release is definitely one of the best parts of any clamp play! Once again, I have to stress, if you have sensitive nipples or have not played with nipple clamps before - TAKE HEED! These are serious clamps for those bondage afficienados! Right up my alley! Have fun and remember to always PLAY SAFE!!!