1). Smart braking rear light, or w/o smart braking function to be used as a ordinary rear light, two versions. 2). USB rechargeable. 3). Auto-sleeping when not moving in 45s. 4). Highlight 3s when speed cut. 5). Including 3 kinds of bracket: for seatpost, saddle, and back clip for bike bag or pack etc... 6). Material: PC 7). Modes: Constant, Breathe, Slow flash, Rhythm flash, flash, strobe 8). Power indicator: 80%-100%, green; 30% - 80%, blue; below 30%, red. 9). USB rechargeable, Type-C charging port. 10). Charging time: 2 hours. 11). Waterproof grade: IP66. 12). Size: 33*33*30mm. 13). Battery: 400mAh. 14). Runtime: 12H at 100% power.