Noise reduction value: reduce noise by 31db
[Instructions for use]1. Stretch the headband to the maximum "open" position and across the top of the head to cover the ear cups.2. Relax the headband back and adjust the height of the cup until the headband can support the cup and both ears feel comfortable for3. The soft pads of the ear pads should closely fit the head.4. Adjust the headband to ensure correct tightening and effectively isolate noise.