Product Details: Sharp 4" BandW Monitor Displays Crystal Clear Images and Audio for Communicating between the Intercom and Receiver"s Location; Binary System doubles as a Door Bell with a "Ding Dong" Chime to notify you that there is someone at your Door or outside your Home or Warehouse; Conveniently View up to 10 Feet at Night in Low Light Conditions; Receiver"s Display will automatically switch off after 80 Seconds of Viewing to Save Time and Conserve Energy; Add up to 2 Additional Receivers for 1 Intercom for Viewing in Multiple Rooms; Easy Installation and Operation with User-Friendly Mounting Hardware and Easy to Read Manual Product Specifications : Monitor : Display: 4” Flat CRT; Resolution: 380 TV Lines; Power Source: AC 120V/DC15V 1A; Current Consumption in Operation: 740mA, Stand-by 63mA; Conversation Time: Automatic turn off after 30 seconds; Call Signal Sound; Operation Temperature: 32ºF to 122ºF; Camera; Image Sensor: 1/4” B/W CCD Sensor; Resolution: 352(V) x 288(H); Lens: 3.6mm Fixed Lens; Source of Illumination: 6 Infrared LEDs; Operation Temperature 14ºF to 122ºF For Additional Product Specifications Please Contact Customer Service at 877-327-5000