The Walker's Bluetooth Passive Earmuffs with Boom Mic offer passive ear protection with the option of connecting to your mobile device through Bluetooth technology. The boom mic is adjustable with a wind screen which gives a distinctively digital clear sound without interference. The Bluetooth Passive Muffs feature an auto shut off a 2, 4, and 6 hours, as well as a new ergonomic head band design for comfort. Powered by two AAA batteries which are included.