Size details :length: 4 cm / 1.57¡±light surface diameter: 2.5 cm / 0.98¡±tail lamp diameter: 2 cm / 0.78¡±Material: aluminum alloyLED: 6 white light、 life 10000 hours、 small power consumption、 high brightness、 light beam stabilitySwitch: switch to the tail push button (two block adjustment、 1= normally lights on 2= flashing)Save electricity、 use 2 CR2032 button batteries. 360 + 135 + 360 ¡ã to adjust lamp to freely.The bicycle light can be placed in the handles、 can be put on front fork、 back fork .Three kinds of modes: flash/steay/offPacking detail: 1pc lamp、 1 pc bracket、 including 2 pc batteries