Lox's unique secure earring back patented technology gives you the confidence to enjoy earrings wherever you go. To use, simply slide on and squeeze off. The clever patented design really grips the earring post, yet it is so easy to release when you want. The clip is made from silver tone stainless steel and the body is made from hypo- allergenic plastic, which is the only part of the Lox that contacts your skin. Each earring back measures 7mm in diameter and 3.4mm in depth.