A clover clamp is a type of clamp, of Japanese origin, designed for "clamping sails or sewing fabric." A tightening chain or cord hangs from each clamp (commonly linking the clamps together but sometimes split). When a clover clamp's chain is tugged, a mechanism tightens the pinch for extra tension and pain. Recommended for more experienced pain play practitioners.

Source: https://en.wikipedia.org/wiki/Nipple_clamp#Clover_clamp

See also:

• nipple torture
• predicament bondage