From the Knit Picks Website:

This is a one circular needle pattern that fits most women to size 15 for men. While this pattern was specifically created as an alternate way of knitting socks with Knit Pick’s Felici self-striping yarns, Knit Pick’s solids, tonals, multis and hand painted sock yarns can also be used as long as there is sufficient contrast between MC and CC. Choose between a wedge heel and a heel flap heel. Directions for both are offered. Also included are two opposing but similar charts, one for the “left” sock and one for the “right”.