Potentially cool little widget but strikes me as pretty pointless. I don't find it difficult beyond reason to calibrate a tank sender on the bench. Clean the reostat contacts, bend float arm, resolder connections, test with an ohm meter. As long as it reads empty before it's actually empty, I'm good.
Well, when you have a stock sender that no aftermarket meter works with it's not pointless. Such as the autometer gauge in my 51 Plymouth.
But if your head revolves around stock only then, yeah, pointless.
