This Homesafe Barking Dog Alarm is a multi-functional system which uses an electronic radar-wave sense control. This technology allows it to see through wood, cement, brick, glass etc. When an intruder enteres the 1000 triangle of protection it automatically begins barking like an angry dog. The barking dog alarm from outside sounds like you have a very unfriendly dog inside. The barking dog alarm can also announce visitors with a chime or alarm. The barking dog alarm has radar sensitivity that is adjustable from 10 to 20 feet. The volume is also adjustable. The barking dog alarm stands 9 inches tall and is powered by an AC power supply. The alarm also takes 8AA backup batteries (not included) in case of power loss. The alarm needs to face in the direction you want to detect motion. Detection is limited from the sides and rear. The dog alarm also comes with a remote control which lets you arm and disarm the system as well as set off a panic alarm. You can also connect one additional sensor: The NA motion or HA sensor.