Designed to be the ultimate rechargeable hearing-enhancing muff, the Walker's FireMax Digital Earmuffs will last up to 150 hours while providing optimum protection. These ear protectors come equipped with a 2000 mAh lithium-ion battery, four frequency modes, and HD speakers for clear, balanced sound. The gel-filled ear pads and rubber tacti-grip headband sit on the head comfortably, while the digital audio circuit delivers blazing-fast reaction time and has an NRR of 20dB.