The Cateye Rapid Micro Rear Light is their entry level rechargeable rear light. It is the smallest & most affordable rear rechargeable light Cateye make. The Cateye Rapid Micro Rear light has a triple LED function & is USB (Universal Serial Bus) rechargeable. It makes an ideal light for commuters who want basic visibility to other road users. Triple LED 15 lumen output Li-ion Battery USB (Universal Serial Bus) rechargeable 4 modes; Constant, Flashing, Rapid & Pulse Runtime: 330 hrs depending on mode Automatic flash when low on battery Battery auto save Low battery indicator Light mode memory