Walkers Digital Muff Firemax Rechargeable Black Black. The Walker's Game Ear FireMax Behind the Neck Muff are the ideal choice for the type of people who want a rechargeable option for hearing protection when batteries aren't close at hand. The FireMax can be charged with a USB-C charging cable to run for up to 200 hours on a charge. Specifications for Walkers Digital Muff Firemax Rechargeable Black: Manufacturer: Walkers Color: Black NRR: 20 dB Condition: New Last Chance: Yes Features of Walkers Digital Muff Firemax Rechargeable Black Slim low profile design Digital audio circuit Rechargeable Low noise/Frequency tuned for natural sound clarity Auto shut off Digital soft touch silent button operation 4 Frequency modes: Universal Clear Voice High Frequency Boost Power Boost Package Contents: Walkers Digital Muff Firemax Rechargeable Black Walkers GWP-DFM: Digital Muff Firemax Rechargeable Black Black