Rex Plus is the electronic watchdog that never sleeps and the soothing sounds of the rainforest Choose from four settings: continual tranquil sounds of the rainforest, alert sound of an angry and protective watchdog, soothing sounds to alert you of a guest's arrival, and alert sounds of both the angry watchdog and a warning siren. Rex Plus can inchsee inch through thick doors, walls and glass. Once you plug his cord into any standard 110-VAC electrical outlet, he'll stay on duty around the clock. Ideal for homes, apartments, mobile homes, RVs, jewelry stores, hotels, public and private buildings of virtually every kind. Choose any location indoors where you want to detect movement such as hidden behind the front door. Turn Rex on and he begins detecting. When movement is detected, Rex Plus will alert you with the sounds you have chosen.