Features: The Rapid X features superior side visibility and a Low Battery Auto Save function, providing a new level of safety. The USB Rechargeable Rapid X provides a bright, powerful glow with incredible side visibility. When the battery runs low, the low battery "Auto Save" function automatically changes the light pattern from the current mode to flashing, providing an additional hour of riding safety. 6 modes. 2 Hour charge time. Tech Specs: Dimension? 74.2 x 24.4 x 30.8mm Weight? 22.5g (with batteries) Light source? COB LED Battery? Lithium Polymer rechargeable battery Runtime? High mode? 1 hr Low mode? 5 hrs Flashing mode? 30 hrs Rapid mode? 16 hrs Pulse mode? 16 hrs Vibration mode? 8 hrs Recharge time? 2 hrs (USB recharge) Mount size? Rubber band mount (fits I| 12.0-32.0mm)