The bluetooth passive muff is a passive hearing protective device that features bluetooth connectivity to mobile devices.It has an adjustable boom mic with wind screen, auto shut off 2/4/6 hours, and is powered by 2 (aaa) batteries, batteries included.Type: Electronic EarmuffColor: Black Ear Cups w/Black BandNrr: 26 dBQuantity: YesStyle: Over the HeadBattery: AAAMaterial: Polymer