Master Series Charmed Heart Padlock Nipple Clamps from XR Brands. These easy to use clamps have a simple screw-down design, accented with heart shaped padlock detailing. The vinyl coated tips allow for a comfortable and secure grip while the black lacquered heart accent dangles enticingly from the end. The screws on the sides allow you to control just how much pressure your partner receives. Measurements: 4 inches in total length, opens to 0.5 inch in width. Materials Metal, vinyl. Color Black.