I really like TYReXCEL's TPMS system. I found it easy to install and pretty accurate. The product comes with 4 valve sensors and a small LCD screen that is either solar powered (with a small solar panel on the back) or USB powered (to connect to a car charger). The installation of the sensors is very easy and fast. Once the sensors were installed and the LCD screen was on, I got pressure and temperature readings. I adjusted the tire pressure before installing the sensors, and after installing the reading was about 1 PSI lower (which can be explained by a slight inaccuracy of either the sensors or my air compressor, or little air lost when installing the sensor) . ), which is reasonably accurate. The only minor complaint I have is that I wish the screen was a little brighter. But that doesn't matter as it's still fairly easy to read the measurements. All in all I recommend this product. 5 Stars.