Includes a wireless sensor wand with a plug in electronic transmitter module. Transmitter has 15" tether designed for mounting away from driveway edge. 2 channel receiver and 2 "AA" batteries included. Internal potentiometer board adjusts sensitivity from 3" to 12" radius to accommodate many applications and situations. Easy installation 2 piece construction, sensing coil and electronics. Compatible with all automatic gate operators or other systems requiring a dry contact input device.