Getting the attention of motorists and others while out on the road is what the Aether Demon Tail Light does best. This incredibly bright, blinking tail light from Portland Design works eschews those clunky alkaline batteries in favor of a sleek lithium ion battery that charges via USB port. With a 0. 5 watt LED from Nichia, an integrated circuit from Texas Instruments, and four distinct operating modes, the Aether Demon has your tail light needs covered no matter where the road takes you. The Portland Design Works Aether Demon Tail Light comes with seatpost and seatstay mounts, and the four operating modes run time are as follows: Dance 8hrs, Breathe 8hrs, Group Ride 175hrs at 10% power, and Rock Steady 3. 5hrs.