USB is rechargeable and easy to use: no longer need to buy or replace the battery of your Luminous Doudou, simply use the standard USB port on your computer or mobile phone charger. Press the button in the middle of the LED light to turn it on/off. Different brightness: three kinds of brightness are available, strong light (lighting for 10 hours), medium light (lighting for 15 hours), low light (lighting for 20 hours) Convenient to Charge and Wash: Simply pull the edge of the sock cap and push the lamp inward to separate them and wash the cap or charge the lamp. The 4 LED lamps have a high quality IP44 waterproof rating. Elasticity and Universal Size: This winter warm LED knitted hat can fit most children, men and women of different head sizes, with high elasticity. Suitable: It is the perfect flashlight for camping, party, cycling, barbecue, car repair, fishing, jogging or walking with dogs on cold winter nights.