Our LED bracelets are made of acrylic, and are great for all occasions! To activate, press the button inside of the bracelet. These bracelets have a diameter of 3.35 inches. Batteries: 3 AG3. Replaceable, included and installed. The Flashing Bracelet is the perfect lighted accessory to attract attention to your brand or awareness party. Good choice for Halloween/ party/ concert/ sports/ music/ celebration/ holiday decoration.