Do you own or play an Autoharp? This would be something you need when tuning the instrument. The lowest note of this instrument is the F, most Autoharp players tune the C's, F's and then the G's followed by the rest of the pitches.
This Autoharp tuning key with a longer handle allows more control as it only requires minimal turnings on the pins when tuning the instrument. Clockwise to raise the pitch, anti-clockwise to lower the pitch.
Also suitable for tuning the hammered dulcimer, zither and psalteries.