Stay safe and visible from dusk till dawn with the NiteRider Solas 100 Tail Light. 100 lumens of powerful LED light are projected into low-lit or dark conditions, so you can stay safe and seen by others. There are two steady modes and two flash modes, including a "Group Ride" mode for cyclists who want to stay visible, but not distract others in the pack. Runtimes range from 4:30 - 7:30 hours of steady light to 10:30 - 15:30 hours of flashing light. It's USB rechargeable in only two hours and low battery indicator let you know when its time to juice up.