A great on-line educational tool, a guitar slide rule that enables you to Find any Pentatonic or Blues Scale in any position and Key for Guitar and Keyboards, great for finding new riffs and scale positions for your soloing and for practicing you scales. Available as Android app too-free. NOTE: The Slide Rule does not play music, it is an educational tool not an entertainment tool. Great for teachers, students, schools, musicians etc. Also a transposing tool, plus a Module for understanding how chords are made and a beginners chord book. Get the The Free Android App:- https://play.google.com/store/apps/details?id=mobione.pentatonic_slide_rule Go to www:- http://www.metsmusic.com/android/