Work Tunes jan15 Comfortable foam face seal Size:10X14" Comfortable foam face seal Fast and easy to set up and stow away Noise reduction rating (NRR) of 24dB or higher when worn properlyEquipped with 40mm high fidelity Speakers for premium sound qualityEasy to use one button interface helps keep you focused on the jobBuilt in rechargeable batteryCharging cord includedVented headband design features removable padding for versatile comfortDurable design is great for everyday useAutomatic shut off helps extend the life of your batteriesVolume temporarily mutes when phone calls and messages are receivedHelps lower your risk of noise induced hearing lossNoise Reduction Rating (NRR) 24 dB*Requires 2 AA batteries (not included)Optional lithium rechargeable battery (sold separately) – 3M™ ALPHA1100 Rechargeable Li Ion Battery Pack for 3M™ WorkTunes™ Wireless Hearing Protector 3M Work Tunes Hearing protector with Bluetooth