Heart Padlock Nipple Clamps Black. These adjustable alligator nipple clamps feature vinyl-coated tips to allow comfortable and secure grip whilst a sweetheart padlock gem dangles from the clamp. The adjustable thumbscrews allow you to choose how strong you would like the pressure, from a light pleasurable sensation to stingingly painful. These high-quality nipple clamps are attractive, easy to use, and great for beginners and more advanced users alike.