?? Headphones functionality??: more than safety ear muffs, they are also headphones, you can enjoy music during downtime via Bluetooth or 3. 5mm audio input (3. 5mm cord is included). No batteries required, The rechargeable battery lasts up to 30 hours after each full charge. The knob allows you to control the volume level with ease (line-in mode only). built-in mic and integrated controls let you make and take phone calls without removing the earmuffs. .
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