The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Nobuko Kitera:
A guitar's scale length is calculated by measuring the distance from the front edge of the nut, where it butts against the end of the fingerboard, to the center of the 12th (octave) fret, then doubling that measurement. Our APP "Good Guitar To Think About From Physics" will do the math as well as help you locate your bridge correctly.You can get the most accurate way to lay out your scale is making all measurements(distance from fret to fret) from the nut by our APP "Good Guitar To Think About From Physics".