Wireless commercial entrance alert with motion sensor. Sensor chimes when motion is detected in entryway. Signal passes through walls, floors, and doors. No wiring required. Plug doorbell receiver into a 120 volt outlet. PIR sensor uses (3) AA batteries, not included. Sensor is rated for indoor or outdoor use. Ideal for use in entryways or as a driveway alert. Features volume control to adjust loudness and includes hardware. Receiver has 3 selectable chimes including 1-note, 2-note, and 8-note Westminster. 2 year warranty. 2.75 inches wide x 5 inches high x 1.5 inches deep. Weighs 0.7 pounds.