This smart brake light Features auto/off, 7 lighting modes, 180 wide field of view, waterproof and dustproof. It is a great accessory for bike riding. Features: Brake light: Turn to high light automatically to warn the pedestrians and vehicles when braking. Auto on/off: With high-precision smart sensor, the light turn on automatically when sensing the vibration, and switch off automatically when there is no operation in 3 minutes. 7 lighting modes: Easily switch among 7 lighting modes by a simple press of the button. Much safe riding: 180 degree wide field of view and up to 100 lumens of brightness ensure good visibility and safety when riding at night. USB rechargeable: Built-in 500mAh battery lasts for 5-15 hours after fully charged. Waterproof: Made from PC plastic, lightweight, waterproof and dustproof. Easy installation: Easy to install on the seat post of your bike with the included rubber rings, no tools required. Specifications: Material: PC Battery: 500mAh Lumens: 100 lumens Size: 7.3 * 2.2cm / 2.9 * 0.9in Weight: 32g / 1.1oz Package Size: 11 * 8 * 3.3cm / 4.3 * 3.1 * 1.3in Package Weight: 61g / 2.1oz Package List: 1 * Bicycle Light 2 * Rubber Ring 1 * Charging Cable 2 * Rubber Pad