The A Phrygian scale has 7 notes: A – B♭ – C – D – E – F – G. Phrygian is a minor scale with a ♭2, one fret above the root. That dark half step gives it a Spanish, heavy feel. In Indian music it is Bhairavi thaat.
Compared with the A major scale it has ♭2 (B♭ instead of B), ♭3 (C instead of C♯), ♭6 (F instead of F♯), ♭7 (G instead of G♯).
The explorer above is set to A Phrygian: the whole neck is mapped, and you can zoom into any of its 7 positions, change the labels to degrees or fingers, and hear it up, down and in patterns.