... back light, all use 4pcs AAA dry batteries. LED Bike Bicycle LightSpecification:-LED bulb:9 LED Ultra Bright White-Length: 97mm ... , etc..-Switch: push button on/off-Waterproof:Splash proof.Battery Replacement-Unscrew the back of the Flashlight-Slide out the battery ... , camping, emergencies, etc Home, office, car, camping, emergencies, etc led bicycle light