Superior visibility day or night 3 x red SMD LEDs – 15 Lumen output USB (Universal Serial Bus) Li-Ion rechargeable battery Supersonically welded for weather resistance Mounting bracket 21.5 – 32mm Light mode memory Battery indicator Battery Auto Save converts to flashing mode so you’re never left in the dark Recharge time: 2 hrs Mode: Output Runtime Constant: 15 Lm 3 hrs Rapid: 15 Lm 5 hrs Group Ride (low pulse): 15 Lm 20 hrs Flashing: 15 Lm 30 hrs