The Cateye Rapid X2 rear light comes with surface-emitting LED strips wrapped in Cateye lens technology to pump out 80 lumens of light for unparalleled safety, day or night. This compact light can be mounted in a variety of positions using the provided bands & it will sit neatly on most seatposts. Its a great light option for daytime road riding or for commuting. The Cateye Rapid X2 is USB (Universal Serial Bus) rechargeable & has the low battery Auto Save function that automatically changes the light pattern from the current mode to flashing, providing an additional hour of light to get you home safely. Ultra bright strip COB LED technology 50 Lumen output USB (Universal Serial Bus) Li-Polymer rechargeable battery Versatile rubber band mounting system (12-32mm ) for seatposts & seatstays Light mode memory Battery indicator Battery Auto Save, converts to flashing mode so youre never left in the dark Recharge time: 2 hrs Mode: Runtime High: 1 hr Low: 5 hrs Flashing: 30 hrs Rapid: 16 hrs Pulse: 16 hrs Vibration: 8 hrs