Power balance 100% Surgical Grade Silicone Wristband Balance Bracelet (Black/Black lettering) size Extra Large Equipped with two, visible Power Balance holograms 3mm thick wristband made from 100% surgical grade silicone that is extremely durable Wristband has 40% stretch feature for extra stretch over the hands Improve balance, flexibility and strength as well as contributing to an overall sense of well being Features a 30 day warranty