Main Features: Built-in rechargeable lithium battery, can be used repeatedly, safe and convenient. Detachable night helmet tail light, easy to remove with Velcro back. Three modes, always on/flashing/warning, one-key switch. IP67 waterproof design, no fear of rain and dust. Can be installed on the rear of the helmet, the rear of the electric vehicle, and the riding backpack. Specification: Material: T6 Aluminum alloy+Acrylic Charging voltage: 3.7V Working voltage: 2.6-4.2V Working current: 30mA Operating temperature range: -20~+55 Waterproof grade: IP67 Lithium battery capacity: 200mAh 3 modes: Steady on/flashing/warning Size: 8.7*3.5*1.5cm Package Included: 1*Taillight 1*USB Cable Note: Please allow 1-3cm differences due to manual measurement. Due to the difference between different monitors,the picture may not reflect the actual color of the item.Thank you! No Retail Box,Packing Safely in Bubble Bag.