4. : The fan and adapter weigh only 220 grams, and you 't feel any burden when you put the fan on your helmet. 1. Compatible and universal: The adapter fits most spring-loaded cap-style helmets. The adapter also has slots for headlights, earmuffs, welding masks. 2. Three-speed adjustment: You can the power button to change the wind speed to suit different environments. 3. Long-lasting work: The powerful rechargeable battery helps the fan run all day with the . 5. Night light: The fan with night light can show you at night or in dark places.