Ouch Adjustable Nipple Clamps Black. These nipple clamps with chain from Ouch! are easy to use and suitable for both him and her. The clamps and chain are made of stainless steel and aluminum, and are completely nickel free. You can use the nipple clamps for your naughty secrets, or for extra stimulation while making love. Length chain 13.97 inches. Materials Stainless Steel, Aluminum, Thermoplastic Rubber.