The mk ii rear light provides 50 lumens of light output from a small light and easy to fit unit 1 pce 30 chip cob high brightness led rechargeable lithium polymer battery 37v 500 mah 8 modes 3 x o rings 20 26mm 26 40mm 40 52mm rubber insert pads allow aero post isp propel and standard post fitting low battery charging amp fully charged indicator automatic fully charged cut off side visibility ipx4 300 degrees total light angle 39 degrees spot angle 29g 93mm x 22mm x 17mm runtimes o