As others have said, the only "instrument" I have ever used to tune my instrument (in this case my drums) are my ears and a drum key. Also, as others have touched upon, there is a sweet spot that the drum wants to be at. Once you achieve that you are pretty much done. Drum dials and the like are marketing gimmicks in my opinion. Never used one, have no use for one, so I'll never own one or buy one.
"Trust your ears"
Coffee Break2