clip. Its serrated jaws are usually covered with removable rubber sheaths to protect the nipple from damage and to reduce pain. This type often comes with screws to adjust the pressure. It can produce a high intensity of sensation, especially if it has teeth, and is mostly used by experienced users. Tweezer clamp A tweezer clamp looks like a pair of regular tweezers. It consists of two short lengths of metal, no more than in length, fixed together at one end and open at the other end. The open ends are curved slightly to improve their ability to grip the nipple. These clamps are lightweight and adjustable and their starting pressure is mild, making them suitable for beginners. They are one of the most popular types of nipple clamp on sale. Typically, they have small rubber sheaths over the open ends for comfort, to protect the nipple from damage and to reduce slippage. A small ring wraps around the two pieces of metal and is used to adjust the tension. The user places the two sides of the metal head either side of the nipple, then by sliding the ring along the clamp shaft towards the nipple, causes the two halves to close tighter together. Tension can thus be adjusted depending on the location of the ring — the closer the ring is along the shaft toward the nipple, the tighter the clamp. Clover clamp The clover clamp, also referred to as "butterfly clamp" or "bird clamp" is of Japanese origin and was designed for clamping sails or sewing fabric. The clamp is flat, about long and wide, and has an eyelet to which a chain or cord can be attached. If this is pulled a mechanism inside the clamp moves the jaws closer together and provides increasing tension. When they are applied to the nipples a spring hinge holds them in place under tension and provides a very high pain level. They are used for nipple torture in the BDSM community. To increase the tension on the nipples, small weights are sometimes attached to the clamps or the chain. These can be weights designed specifically for this purpose or weights such as fishing sinkers can be used. Another use for the clamps is to keep a person in one place. If a cord is tied from the clamp to a fixed place, the wearer of the clamps cannot move