Check the listing for details. ISOtunes LINK 2.0 Bluetooth Earmuffs: 25 NRR, 50 HR Battery Life. Condition: New. Listed at 119.99 USD. Earmuffs. Done Better. Our best-selling earmuff got an upgrade. Featuring a padded headband cushion, up to 50 hours of battery life and a boom microphone (sold separately) for crystal clear calls, LINK 2.0 is the Bluetooth earmuff you've been waiting for. MASSIVE BATTERY LIFE: Included rechargeable lithium ion battery provides 50 hours of battery life on a single charge. Optional AAA batteries (3) provide up to 100 hours of battery life (not included)UPGRADED COMFORT: Padded headband insert provides improved comfort. Raised buttons provide easy and convenient controls.NOISE ISOLATING HEARING SAFETY: ANSI-Certified 25 dB noise reduction rating (NRR) to limit hearing damage in loud work environments.SAFEMAX TECHNOLOGY: 85 dB volume limiter ensures that your music is always at a safe listening level.WIRELESS CONNECTIVITY: Listen while you work without the wires using upgraded Bluetooth 5.0 technology.BUILT TO LAST: Durable collapsible design with comfort fit ear pads and IPX4 water resistance. ISOtunes LINK 2.0 comes with a rechargeable lithium-ion battery and micro-USB charging cord.