The concept behind this CD is that pupils will enjoy learning scales more if they have extra help at home. Each CD takes you through the scales for each grade with a pretty standard piano harmonic accompaniment. The CD is comprehensively cross-referenced so that you can play the same scale set for another grade at a different speed.
Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).