Walker’s Razor Slim Electronic Quad Muff with Bluetooth. Ultra-low profile ear cups with rubberized coating. Bluetooth sync with compatible mobile devices. Four hi-gain omnidirectional microphones. Sound dampening composite housing. Sound Activated Compression starts after 0.02-sec reaction time. Low noise/frequency tuned for natural sound clarity. Recessed volume control knob on the external battery door. What’s in the Box. Walker’s Razor Slim Electronic Quad Muff with Bluetooth (Black). 2 x AAA Batteries.