The transmitter is mounted on the back of the mailbox post and the drive curls around behind the mailbox so the only alarms are from something on my property. I've had a few falses from deer and the neighbor's lab. but it always has been some object crossing the beam. It is really sensitive, usually get two rings from a semi as it counts the cab and then the trailer.
I've had it a little over a year which means the transmitter battery will go dead today
the receiver unit has a wall wart and a 9v backup battery.
The transmitter is green. I painted it white with some spray paint that is made for plastic so it blended in with the white mailbox post.
there is provision for monitoring a second transmitter and I plan to add that for the back road into our place.
Jim