WOTOW Bicycle Cycling Tail Light Water Resistant 5 Leds 3 Modes Back Rear Red Light Flashlight Lamp Five super-bright red extreme LEDs and three modes remind someone else of keeping distance 3 modes: steady, flashing, blinking Weather resistant build, safer in water fog when riding in the rain Battery by 2 AAA batteries (not included), 15-80 hours depends on the batteries and modes. Quick mount without any tool, quick release.