The main types of nipple clamp are the clover clamp and the tweezer clamp. The common household clothes-pin is also popular. However, any device that can be used to apply direct pressure can be used. For self-use, successful application requires the user to find a personal balance between the amount of pain and pleasure by fine tuning the degree of pressure exerted by the clamp. The clamps are typically used in pairs and connected by a chain.