Specification: [Name]: Unisex Kids Integrally-molded bicycle helmet [Specifications]: One-piece design, very good strength, ventilation hole design, stylish and beautiful color matching [Color] :8 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 58-61CM Material: Shell PC + liner black EPS integrated molding Weight: S:320g L: 360g M: 340g Head size: L: 58-61cm M: 54-57cm S: 48-53cm Helmet size: L: 27.5*21*16.5cm M: 26.5*20*16cm Lighting mode: 1. The front light and rear light are always on 2. The front light is always on and the rear light flashes quickly 3. The front light is always on and the rear light is flashing 4. The front light is off and the rear light flashes quickly Battery: 750 mAh Charging time: 2.5 hours full charge Standby time: 160 days Life time: more than 10 hours (most power consumption mode) current 3.78v, headlight power 150A, rear light power 314A