This innovative unit installs easily without the need for wiring. Place the photocell unit on a porch, entryway, mailbox, or anywhere you want to monitor. The indoor unit may be up to 100 feet away. When triggered, the indoor unit turns on a table or floor lamp, giving the appearance from the outside that someone is home, as well as sounding an audible alert tone. Outside unit has an operating range of -20 to 120 degrees Fahrenheit. The motion sensor uses two AA batteries, which typically last one year. White plastic housing. Indoor unit has manual lamp override, volume control and timer control to adjust length of time the light stays on. Plugs into any standard wall outlet. White finish. Takes two AA batteries (not included). Override, volume and timer controls. Plugs into any standard wall outlet. Outdoor unit is 3" high and 3" wide. Indoor unit is 3 1/2" high and 3" wide.