UsesConcentrate, protect hearing, etc. It is a good helper for you to avoid noise interference at home, dormitory, self-study classroom, traveling by car, ship, plane, factory, construction site, bustling urban area, etc. It is a good partner for your healthy new life, and it is also your watch F1 race. effect Noise reduction rate (NRR) 26 decibels, multi-point wearing; the headband is equipped with a comfortable pad, and the adjustable headband ensures three positions of the headband (top of the head, back of the head and chin), which is hygienic, safe and soft to wear Comfortable, good sound insulation Instructions for use 1. Stretch the headband to a larger "open" position and cross over the head, covering the cups over both ears; 2. Loosen the headband and adjust the height of the cup until the headband can support the cup and the ears are comfortable; 3. The cushion of the earmuffs should be close to the head without leaving any gaps; 4. Adjust the headband to ensure correct tightening and effectively isolate noise