tire pressure monitoring system

I bought this one last year: https://amzn.to/2J6SAcN
6 monitors for the coach and 4 on the toad. I thought I paid about $50 less that what I see it for now. After using it for 15,000 miles I am very happy I purchased it. Its saved my bacon twice when the inner dual wheel valve decided to leak, on two different wheels at different times. I wouldn't drive my coach without it now. At first I wasn't sure about spending so much money, but now it seems like one of my smarter purchases. -Bill