Rex Plus II, the electronic watchdog alarm from STI, provides a way to deter burglars, without the problems of owning a real dog. With his electronic radar eyes, Rex II can “see” through thick doors, walls and glass. When movement is detected, he starts to emit the selected sound (Dog 1, Dog 2, 2 Dogs together – Ding, Ding Dong, Chirp – Siren 1, Siren 2). The closer an intruder gets, the more frequent the barking becomes. As the intruder backs off, the barking decreases in frequency, stopping completely when movement is out of range. Water resistant flip top provides easy access to the controls. Simply plug unit into a standard electrical outlet or power with six (6) C batteries. Detection range: adjustable up to 26 feet (range reduced through obstructions), detection angle: 150 degrees. Easy setup with voice messages or prompts.