I know there was a thread a while back about TPS systems. I have a Tire Safe Guard system and highly recommend it. It is reasonably priced, has flow through sensors with replaceable batteries available, and reaches the toad from the back of my 40 ft Berk. The icing on the cake is, however, that tech support is available all the time. I called yesterday (Sunday) around 7 pm to get some advice on a programming issue. I figured I'd get an answering service, but got a live human being who fixed my issue in about 30 seconds. I've had the system for about two years and have had no problems at all.