Easy to install and use. I charged it before installing and using it for the first time and I have never seen the battery indicator fully charged as it is charged by the solar panel. Works on every car, I've even tested it on our bike tires. Each sensor weighs approximately 0.4 ounces. Ideally you should install them PRIOR to balancing the tires, but I have not noticed any deterioration in balance after installation. Our other car has a TPMS system built in, but it doesn't indicate WHICH tire the problem is like this system does, and this system also has a temp gauge and adjustable settings for high temp and low pressure/high pressure. BAR or PSI, temperatures F or C. Excellent system, especially for long drives in older cars.