Specification:[Name]: Unisex Kids Integrally-molded bicycle helmet [Specifications]: One-piece design, very good strength, ventilation hole design, stylish and beautiful color matching【Color】:4 colors available【Size】: S Size: Suitable for head circumference 48-53cm;M size, suitable for head circumference 54-57CM;L size, suitable for head circumference 58-61CMMaterial: Shell PC + liner black EPS integrated moldingWeight: S:320g L: 360g M: 340gHead size: L: 58-61cm M: 54-57cm S: 48-53cmHelmet size: L: 27.5*21*16.5cm M: 26.5*20*16cm Lighting mode:1. The front light and rear light are always on2. The front light is always on and the rear light flashes quickly3. The front light is always on and the rear light is flashing4. The front light is off and the rear light flashes quickly Battery: 750 mAhCharging time: 2.5 hours full chargeStandby time: 160 daysLife time: more than 10 hours (most power consumption mode) current 3.78v, headlight power 150A, rear light power 314A