The P500-50 Basic Probe is a sensor that detects the passage of vehicles. It is designed for direct burial at the edge of a driveway up to 14 feet wide. If in the center of the driveway, the driveway can be up to 28 feet wide. This Probe has wire lead of 50 feet. The wire is 22/2 shielded with drain. Any single probe will illicit an alarm regardless of vehicle direction. Two probes used in conjunction can create a directional system.