CARCHET&reg; 2 Black Skull Bike Bicycle Safety Rear Wheel LED Flash Light Lamp Light color: white 2 flash modes: fast flash and steady light Made of flexible and waterproof silicone Easy to install and remove without tool Can be easily mounted on 10mm-35mm tube;Powered by 2 Pcs CR2032 batteries (included);Suitable for bicycles, backpacks, helmets etc.;100 hours of extraordinary lighting time;With two ultra-wide-angle LED, providing high brightness 20000mcd, the warning distance over 600 meters;Weight(g): approx 30;Package included:- Bicycle light x 1- CR2032 button batteries x 2