I have a car with a bad TPMS sensor. The car doesn't tell me who has the problem. It only indicates that everything is ok in the absence of a signal lamp, or that everything is not ok with a single lamp. Given the age of my car, it's probably a dead battery and it's advisable to replace the other three at the same time. Until I can, this product allows me to quickly confirm that all of my tires are indeed at the recommended pressure during a safe ride-through. They are also present after replacing my sensors. The direct visual confirmation is reassuring.