The Radians Vertex low-profile earmuff provides all-day comfort and NRR 22 hearing protection. The premium earmuffs feature micro-circuitry for standard and enhanced amplification with no lag time to protect against dangerous impulse noise. The right and left earmuffs have independent microphones for directional input. The earmuffs are powered by a rechargeable lithium-ion power cell for longer run times. 312 zinc air cell hearing aid batteries with up to 120 hours of battery life.