Welcomeuni Bicycle Safety Lighting LED Light Lamp Flashlight Bike Bright LED light, energy saving, low power consumption, long service life Light weight, easy to use and carry ; 2 LED lamps. 3 flash function: steady, storbe flash, slow flash; 2 CR2032 batteries (Included) Stretched length from 9 to 13 cm ; Can be mounted on handlebar, seatpost, helmet, wheel, hub, etc Do not turn on/off lamp while riding bike