Guitar Fretboard: Scales is a multimedia application designed for iPhone users to enhance their musical skills by focusing on scales and fretboard memorization. This app provides a customizable interface that allows users to display scale or chord notes and intervals on a guitar fretboard. It features over 45 scales and 35 chords, offering a range of options including Major, Harmonic minor, and Exotic scales, making it suitable for both beginners and advanced players.

In addition to its extensive library, the app includes interval and ear training tools, the ability to add custom scales and tunings, and various display options. Users can highlight intervals, toggle visibility of notes outside of a scale, and switch to left-handed mode. The app also supports zooming and features a dark theme for enhanced usability. Overall, Guitar Fretboard: Scales serves as a detailed educational resource for musicians looking to deepen their understanding of guitar scales.