Functions: Self-powered by the bottle dynamo and use as bicycle light, warning Cranking for power generating and accumulating in high-efficiency High-luminance lighting Charging other digital things to meet an emergency Features: Powered by the bottle dynamo at anytime and anywhere Use as bicycle light for lighting and flashing warning. Headlight lights in high intensity, taillight flashes in red for warning. Make you safe and convenient to ride a bicycle at night Convenient to use as a bicycle light or a dynamo torch Self-powered by the bottle dynamo and cranking to recharge, no external batteries needed, rechargeable power-storage, green power, Eco-friendly, economical and safe (no need to worry about battery leak) Professional ergonomic design, brushless generator used. Perfect combination of the light weight and high efficiency. Low noise and long lifespan Unique spotlight system, good for short and middle range distance lighting High-efficiency emergency charger