TST Tire Pressure Monitoring System

I have the 507 system. I pull double and have 12 sensors. i started out with 4 flow through sensors and they were sooo slow to put air in the tire and to long. customer service was awesome and traded them out for no charge. I had to get the repeater, everything works great. my only complaint is the configuration of the monitor makes it so I have to have 3 monitors to get the combinations of which trailer Im towing