The topeak redlite aero usb rear light slim aerodynamic rear light with a maximum 55 lumens perfect rear safety light for any cyclist topeak redlite aero usb rear light features rubber strap allows tool free mounting and removal low battery indicator 76x34x31cm 42g lamp 3 super bright ledrsquos battery 37v 640 mah lithium modes high beam low beam blinking pulse burn time approx 2hr high 4hr low 15hr blinking 50hr pulse charge time approx 2hrs