Tire Monitors

I have a TST 507 flow through. My personal experience - I have had one sensor completely fail due to corrosion inside the sensor and 2 don't actually flow through. You have to remove those sensors to air up. Not a huge deal but sort of makes the flow through option a moot point. That said, the unit works great, fairly accurate as I can tell and TST is fabulous with customer support. They replaced my defective sensor for free and they are very nice and well informed when you call with questions. 4 stars. I'd give 5 but the one defective sensor and the fact that 2 won't air up with it on forces my hand. They did tell me that with extensions they sometimes won't air up, I tested this on my truck and they were right. So maybe it's less of a design/product issue and more of an issue with the extensions. Most people have extenders on their rear duals though so you would think they would have worked through it, but at least it's explainable.