Uniden USHC41 Video Surveillance Uniden Smart Home Security System, White (USHC41) Gateway with built-in Siren will sound when Armed system is triggered Door/Window Sensors wirelessly sends a signal to the Gateway indicating something has opened. The On/Off Switches can be used to turn lamps on and off wirelessly as well as turning off appliances when not in use Supports up to 24 sensors Supports up to 4 AppCams and/or Guardian Systems