Communicate freely without removing your respirator Clear voice communication through a light-weight, unobstructive loudspeaker Long-lasting standard 9V battery. Widely available, easy to change Pocket-sized amplifier/loudspeaker Rugged construction, designed to withstand temperature, vibration, impact, dust and spray Thin, flexible cable — can be worn inside clothing The microphone is mounted in the protective cap at the speech diaphragm of the respirator, which means that it can be attached and removed without any permanent modification or intrusive alteration of the respirator The loudspeaker unit can be clipped onto a breast pocket, waist belt or shoulder strap Battery: Accepts standard 9V alkaline or rechargeable battery Microphone: ELECTRET type Loudspeaker: 50 mm (1.97"), Mylar cone, 8 Ohm, 2 W Dimensions (speaker unit): 64 x 96 x 35 mm (2.52" x 3.78" x 1.38") Weight: 146 g (5.15 oz) (without battery)