The Aquacom® ComBox is a compact, self-contained one diver air intercom. It allows clear two-wire communications using a powerful 20-watt amplifier and a powerful front panel speaker, “Silver Bullet”. The ComBox is rugged and offers many features others dream about. The Push-to-Talk (PTT) control is an industrial grade switch designed to be pushed all day long. The front panel speaker is small but packs a lot of sound. In hi-noise environments or where privacy is a concern, the optional deluxe headset is available. In all, the ComBox is the finest one diver box on the market. 6 hours continuous use with Alkaline batteries. Frequency Response: 600 to 10,000 Hz. Output Power (watts): 20 Controls: Volume: Tender, Diver 1 Speakers: Heavy duty, “Silver Bullet” front panel (10 full watts) Low Battery Indicator: n/a Battery Type: (16) AA Alkaline batteries or 12-volt front panel option Dimensions (W x H x D): 9″x7.85″x 3.4″ Weight: 5Lbs.