The compact and innovative ring rear light generates 25 lumens of light from the lightweight unit features 1 pc 15 chips round ring cob high brightness red led cnc aluminium heat sink casing rechargeable lithium polymer battery 37v 280mah 6 modes standard high over drive 20 flashing 100 flashing strobe quick release universal bracket rb 22 fits all round bars and aero style bars 2 o rings for mountingrs g fits 20 35mm diameters rs h f