The Cateye Reflex Auto Rear Cycle Light and Reflector has been designed to exceed the bike light standards in the UK, Germany, USA and Japan. Under UK regulations you should have both a red rear light and a red reflector when riding at night. The Reflex Auto gives you both.The Reflex Auto will automatically turn on whenever both darkness and motion are detected by the built in motion and light optic sensors. This provides the rider safety both while the light is turned on and while functioning solely as a reflector.Features5 LEDsGreater than 180 degree visibilityAutomatically turns on / off by light and motion sensorsEmits light for 50 seconds after the bike stopsBuilt-in reflectors that meets highest government standards (USA, Great Britain, Europe and Japan)OptiCube lens technologyAAA alkaline battery x 25 modesMode memory functionSP-5 bracket (21.5-31.8mm) and Rear rack bracketWeight 82gDesigned in JapanRuntimeConstant mode?30hrsFlashing mode?100hrsRapid mode?60hrsLong-life mode?120...