Be seen when it matters most! Super bright 30 lumen COB rear light with safety brake light function. The light will automatically detect the riders speed slowing & shine brighter under braking or glow constant under braking when in flash mode. Micro USB (Universal Serial Bus) recharging. Stay safe at any speed with this innovative back light that gets brighter when you hit the brakes. The lumasense uses an accelerometer to boosts brightness as your speed slows alerting the traffic behind you. Powered by Chip-On-Board (COB) technology its 30 lumen beam is housed in a compact tough nylon case. Lumen Output: 30 Burn time: high 8 hours med 9 hours flash 12 hours strobe 12 hours USB (Universal Serial Bus) Rechargable Waterproof: IPX5 Lithium ion battery Colour: Black