An all-new high-performance digital circuit delivers blazing-fast reaction time, ensuring optimum hearing protection. Advanced Digital Circuit. Active Dynamic Sound Suppression. Hi Gain Omni Directional Mics. Clear digital sound. Lightening Fast reaction time. Wind noise reduction. Auto shut off 2/4/6 hours. NRR 23. New ergonomic head band design. Powered by 2 (AAA) batteries -included.