CycleAware Laser Shark Rear Tail Light 2 red lasers with 2 modes, 5 red LED's with 3 modes Burn time laser: 5 hrs. constant,/10 hrs. flashing, Burn time LED: 100 hrs. constant/200 hrs. flashing Visible up to 600 feet away, Weather and shock resistant Universal seat post attachment bracket, 2 AAA batteries required (not included) Tools required: 6mm Phillips screwdriver