The Mighty Mule Driveway Gate Opening Sensor System is an electronic vehicle detection device based on the science of electromagnetic induction. All the electronics are built-in the sensor package that is supplied with 50ft. of underground burial cable. The gate opening sensor responds to the movement of a vehicle only and is unsuitable as a safety loop. It detects a 12' radius and is designed for the inside of the fence. Mighty Mule is a registered trademark of GTO Inc.