UltraTuner is the most precise digital tuner available for iOS, providing precision down to .01 (yes, that’s 1/100th) of a cent. UltraTuner is 10x more precise than mechanical strobe tuners, which are generally considered the “gold standard” of precision tuners, and they typically don’t fit into your shirt pocket.

This looks very cool. The screenshots of it on the Apple Watch are just great.