When used with the Wireless LED Flasher You See Alert Receiver Model A0211 Item 840211 (available separately), this VideoPhone Transmitter alerts you to incoming calls with a flashing light. In addition, you can easily adjust the frequency code setting so that a neighbor's unit won't conflict with your system. Product dimensions (imperial): 3 inch H x 1.75 inch L x 1 inch W Product dimensions (metric): 76.20 mm H x 44.45 mm L x 25.40 mm W