RadioShack Advanced 3-Station/3-Channel FM Wireless Intercom (43-3105) Product Type- Wireless Gray; Built-in Speaker, Microphone; 3 per pack Attached 6.5', 3 Sprong AC Power Cord Control Volume and Power; Lockable talk button to monitor another room with confidence; FM circuitry provides clear, reliable reception and transmission; Call button signals other stations 3 Channels( A-200KHz, B-270KHz, C-230KHZ); Transmission Range - 300 feet