The WPA-3000 is an extremely reliable driveway alarm that is used to detect vehicles only. The transmitter operates on one 9-volt battery and has 50' of direct burial wire connecting the probe to the exterior case. The probe is buried parallel to the driveway, and will detect vehicles passing by within approximately 10-12 feet. The direct burial cable can be run to a tree or post nearby, where the transmitter box is located. When a vehicle drives by, the transmitter will send a signal to the WR-3000 receiver up to 600 feet away*. The WPA-3000 is ideal in locations where there may be deer or other large animals that would cause false signals with a motion detecting system. Also, because the probe is buried underground, it will be the least noticeable of our wireless systems. The transmitter is weatherproof and meant for exterior locations. Up to four zones can be monitored with additional transmitters. The transmitters can be programmed so they will each sound a different tone at the receiver. more info