This Howard Leight Impact Sport Earmuff offers superior hearing protection for shooting while keeping you safely connected to environmental sounds. Digital sound compression provides a lightning-fast .5 millisecond reaction time (the interval between when a shot is fired and when the earmuff lowers the sound to a safe level). The 21 dB NRR (Noise Reduction Rating) makes the earmuff ideal for hunting and shooting at the range. Two high-gain omni-directional microphones deliver 5X sound amplification of low level frequencies. This allows you to hear important commands on the range and crucial environment sounds when hunting. Integrated Bluetooth technology allows the electronic earmuff to sync with your mobile device for seamless music streaming. You can also make safe hands-free phone calls and stay connected with others at the range or on the hunt. 21 dB Noise Reduction Rating (NRR). Faster Sound Activated Compression: 0.5 Millisecond Reaction Time. Bluetooth Sync to wireless devices with integrated headset controls. Digital compression circuitry with 5X Sound Amplification Separate Volume Controls for Bluetooth and external environment amplification 2-High Gain Omni Dircectional Microphones Features AIR FLOW CONTROL that allows for a slim low profile ear cup design ensuring firearm stock clearance Compact folding design for convenient storage Automatic shut off engages after 4-hours to conserve battery life Rechargeable Lithium Ion Battery with USBC Recharging Cable