These nipple vises are not for the faint of heart! Padded for protection, yet sturdy enough to clamp on and stay where they are placed. You can control how powerful the pinch is by twisting the screw. These nipple vises have no strings in them and are held on with only the squeezing power of the vices. This style of nipple vise is far more comfortable than nipple clamps to wear during play. A high quality nickle free chain joins the vises together for added sex appeal.