Double bracket design, compatible with seat post and seat rail installation, offering flexible mounting options Exterior constructed from aluminum alloy for durability, strength, and style Optimized optics provide bright, even illumination with reduced glare Tool-free installation: quick and easy setup on seat post or seat rail with one-button operation Seven-color LED lighting modes deliver vibrant light effects Five lighting modes offer versatile visibility options for night riding Real-time power level indication via four central LED indicators for convenient charging management Water-resistant design withstands rain and adverse weather conditions (Note: not intended for prolonged submersion) USB rechargeable with built-in 300mAh lithium polymer battery Color: Black Material: Aluminum alloy Size: 3x3.4x3.4cm Package Contents: 1 x Taillight 2 x Mounting straps 1 x Seat post bracket 1 x Seat rail bracket 1 x USB charging cable Content limited to items listed above; additional products not included Note: Lighting and display settings may cause slight color variation between image and actual item. Measurement tolerance +/- 1-3cm