Our two channel FM wireless intercom system allows a choice of two channels to talk to or monitor any number of rooms or offices. The FM-200A simply plugs into any AC outlet. It features a lock button, which allows for continuous talk. It is capable of up to a 1500 ft range. The intercom has adjustable volume controls with low, middle and high levels, and even a call feature when not in lock mode. This model replaces our FM-200. This intercom is also available in a three channel version under model number FM-300A. FM-200A Technical Specifications Channels 2 Power Source 120V AC Carrier Frequency Channel A 230 kHz, Channel B 260 kHz RF Output Power 100 mW Audio Output Power 500 mW Modulation Method Frequency Modulation (FM) Transmission and Reception Phase Locked Loop (P.L.L.) Dimensions 5 1/2" L x 5 1/2" W x 1 1/2"H (1 unit) Weight 1 lb (1 unit)