Easily monitor vehicle traffic and pedestrians in two locations with this driveway motion sensor alarm. This motion detector kit is perfect for industrial or residential properties that require snow plowing, have heavy truck traffic, must monitor forklift traffic, or can't use driveway signal hoses in their driveway alert systems. The TWO wireless driveway alarms do not use an air hose â?? instead, they detect movement up to 25' in front of it and rings the receiver chime each time the movement is detected from up to 1/2 a mile away. The sensor uses a 9 volt transistor battery. The chime plugs into an ordinary electrical outlet, and produces a soft ring with a built-in audio volume control. The driveway chime alarm will play one of twelve different tunes that are selected in the sensor. "Original" Bellâ?? is wired to the chimes using 5â?? of low-voltage electrical wiring included with this kit. The chime has volume control and can be turned up loud enough to be heard through the door of many houses. The driveway motion detector chime kit includes all of the pieces necessary to set up your wireless driveway alarm and bell