Jawbone UP MOVE MultiColor Replacement Wrist Band (Thick Black) Flexible and comfortable to wear day and night, and with it's adjustable clasp you can size it to fit any wrist. Optimal for tracking total sleep, light sleep and sound sleep with your UP MOVE Wristband ergonomic, durable, moderate softness, very comfortable to wear, the size of the individual under the circumstances to adjust the wrist Made with medical-grade rubber PC lock using environmentally friendly materials to manufacture molding, drying surface texture processing, no harm to human skin, environmental safety