AP Products | Propane Tank Gas Level Indicator | 024-1000

Very easy to install, especially on a dual, stand-up 20# tank setup. The directions are slightly misleading, but their are only two components -- the monitor and the two exact sensors. My only reason for not going with a five star rating is because both of my tanks are full (which is shown correctly on the monitor); and I have not used the tanks enough to see how accurate the monitor readings are when the tanks start to drain.