The Secure Pro keypad alarm system utilizes magnetic sensor technology to protect homes, businesses, garages, sheds and more from break-ins or home invasions. The magnetic contact alarm will sound whenever a door is opened either immediately or after a 10 second entry delay. In addition to a 110 dB alarm it has a chime that can be used to let parents know if a child has gone outside or a store owner if a customer has entered their shop. It also features a panic button to activate the alarm during an emergency. It is easy to install- no wiring is required. Uses three (3) AA batteries (not included). The main unit is 5 1/4 inches x 3 inches x 1 inch.