This Impact Sport earmuff has a 21 dB Noise Reduction Rating (NRR) and a digital compression circuitry with 5X sound application. It features a faster sound activated compression at a 0.5 millisecond reaction time. Equipped with Bluetooth® technology this allows you the ability to sync your wireless devices to the earmuff. The headset has separate volume controls for Bluetooth® and external environment amplification. External environment amplification uses a 2-high gain direction microphones. Impact Sport earmuff has AIR FLOW CONTROL that allows for a slim low profile ear cup design ensuring firearm stock clearance. Adjustable headband now available in two different sizes for a more custom secure fit and a compact folding design for convenient storage. Automatic shut off engages after 4-hours to conserve battery life. Comes with a rechargeable lithium-Ion battery with USBC recharging cable.