This is the topeak redlite aero rear light this is a slim aerodynamic tail bicycle light that fits your seatpost or seatstay perfectly a compact and powerful tail light that provides excellent visibility in any situation the rubber strap mount allows for tool free mountingremoval and multi mounting positions this aerodynamic rear bicycle light has 2 light modes constant and flashing and has a run time of 40 hrs 80 hrs the leds are angles to provide maximum visibility a great lightwe