Unique design，anti-swing and special groove design inside the flex 2 wrist bands with extra clear silicon fastener ring, double secure to prevent the end of the flex 2 wristband from sliding out Two sizes available, small size fits for 5.1"-7.0" wrist. Large size fits for 6.1"-8.5" wrist. Please choose the right size while placing flex 2 sport bands The flex 2 adjustable band is made of a flexible, durable material. Easy to take on and off, the fine craft make flex 2 band easy install and one button disengage it from your flex 2 easily, provides you comfortable wearing experience Classic and Elegant bands will be one of most excellent gift for yourself, your family and friends Two sizes available, small size fits for 5.1"-7.0" wrist. Large size fits for 6.1"-8.5" wrist. Please choice the right size while placing the flex 2 bracelet. The color of the picture might be slightly different from the product due to the difference of screen resolution.