Extra transmitter for the Wireless Probe Alert 3000. The WPT-3000 transmitter is used with the Dakota Alert WR-3000 receiver. The WPT-3000 transmitter uses a magnetic probe and 50 feet of direct burial cable to detect vehicles at the monitored location. When the transmitter detects a vehicle it will send a signal to the receiver which will sound one of 4 different tones (Classical , Westminster Chime, Ding Dong, Whistle) for a few seconds. The transmitter can be used to monitor driveways, drive-up windows, etc. The transmitter is weatherproof and meant for exterior locations.