Old meets new. When a car or truck rolls over the rubber hose (old school), the transmitter sends a radio signal to the DCR-2500 receiver and a chime sound is played at the remote location (new school). The rubber hose stretches across a driveway and the pressure of a heavy car or truck causes the transmitter to send the signal. You can plug the receiver into a standard wall outlet up to 2500 away from the transmitter and it will play a chime sound.
The DCHT-2500 is the transmitter only and must be used with a compatible receiver, either the DCR-2500 desktop receiver, or the the PR-2500 portable receiver. The DCHT-2500 comes with 25 feet of 3/8” diameter rubber hose connected to a wireless transmitter, powered by a 9-volt battery (not included). It will transmit a signal up to 1/2 mile away to one of the compatible receivers. Environmental factors such as terrain, building materials, and other factors my reduce the range.