The go-to tuner app…right up until iOS 9

Use to be that the app had trouble down at E1, but iOS 9 moved that from an occasional annoyance to major PITA with a shift of issues from E1 to E4 (and what guitarist really uses his or her B or E4 string, anyway?). Save your money and get Cleartune or similar.

MDLuthier about GuitarToolkit - tuner, metronome, chords & scales, v2.5.2