Sizes - Child med/lge & Adult sm/med/lge

The diagonal pattern on these thick socks is nothing more than a knit 2, purl 2 rib that shifts laterally 1 stitch every round. Because of this shift, the knit and purl stitches in the rib line up diagonally rather than vertically, and produce a flexible but non-binding leg.

~ From Getting Started Knitting Socks, pg 92