Headset fits under PASGT, MICH & ACH helmet systems Effective sound insulation: 27 decibels Noise reduction pick up edition operated by 2x AAA battery with waterproof battery cap,about 5 hours working time by 2x AAA battery ( not included ) Note 1: This product needs to use with PTT (not included). Note 2: 2 * AAA batteries are needed (not included). Specifications: Applicale Head Circumference: 52-64cm Applicable Scene: Airsoft, paintball, hunting and other tactical activities Material: ABS+Rubber Color: Black, Green, Tan (Optional) Main Item Weight: 360g Daily care: when you do not use this product, please keep it in a cool and dark place and prevent sun exposure. About the battery: please use the battery with specified capacity of this product; don’t use the rechargeable battery; if product don’t use for a long time, please remove the battery. About cleaning: the earmuffs should be cleaned regularly(only clean the surface of the headset,do not soak), do not use solvents to clean the headset and don’t clean the soundproof cotton in side the earmuff. Regular checking: check for cracked or worn parts to see if there are any unsealed position.when necessary,replaced it in time. Package Size: 27.5*20.0*14.5cm / 10.82 * 7.87 * 5.70in Package List: 1 * Headset Package Weight: 490g / 17.28oz