The tail light is made of an aluminum alloy body that can be attached neatly. 1 red LED; 2 modes of light/flashing; Lighting: 60 hours, Flashing: 120 hours; Comes with 1 rubber strap for seat post; Mounting diameter: 0.7 - 1.3 inches (19 - 32 mm); Coin shape for monitors; 2 lithium batteries included (CR2032); L3 x W40 x H28 mm; The design, specifications, and appearance of the product may change without prior notice. We appreciate your understanding.