Instruct: Classify the given review into positive or negative sentiment.
Query: Useful tool for motorhomes, and vehicles that sit...

My motorhome has elaborate charging and monitoring for the house batteries, but nothing for the starting battery. This is an excellent tool to use to keep track at a glance to make sure the starting battery isn't allowed to get too low before taking some means to charge it. Don't expect accurate readings, as mine was reading about 0.5 volts low compared to a real voltmeter (until I opened it and adjusted the little pot).Still, even without adjusting, if you park it, note whatever it reads fully charged (actually about 12.65V), and once once you see it has dropped a half of a volt, it is time to charge. I suspect they are all set a little different.Well worth the price, but fragile as noted earlier.