I just installed the TST 507 on all 10 of my tires. Installation was a breeze. So far, seems to be working flawlessly. I went with the cap type sensors rather than the flow through type that let you add air without removing the sensor. The flow through are just too long and would have made it nearly impossible to add air on my inward facing extended valve stems. Lately I've had problems with Amazon and some of their resellers. So, I found a vendor called "Mobilemusthave", a mom and pop family operation out of northern Michigan. They sell the TST systems at a competitive price with free shipping. Items arrived within a few days and no hassles. Now, I can't imagine not having a TPMS on my rig. Good luck.
2014 Renegade Classic, 45', Freightliner Cascadia 126
Cummins ISX15 with 13 speed Eaton auto shift
1999 Jeep Wrangler toad