VISIBILITY & SAFETY: You can adjust the brightness by pressing the button. There are 3 levels for you to choose the most suitable brightness. It can last up to 10 hours at the lowest level, 4 hours at the medium level and 2 hours at the highest level. USB RECHARGEABLE: The LED light is rechargeable and removable, no longer waste your money on batteries. You can remove it to charge by laptop, power bank, socket, car charger, etc. It takes about 1-2 hour to charge fully and lasts 2-10 hours working time. CONVENIENT CHARGE & WASHABLE: only needs to pull the edge of the hat and push the light inward to separate them and wash the hat or charge the light, the LED lights has high quality IP44 waterproof grade. ELASTIC & UNIVERSAL SIZE: 27*16cm, this winter warm LED knitted beanie hats fits wide range of head sizes for most children, flashlight hat for camping, party, cycling, grilling, car repairing, fishing, jogging or walking dog in the cold winter night.