Pattern uses Hooks G ( 4.25mm) for size 6-12 months and Hook H (5mm) for all the other sizes . It is written in standard American terms. Pattern includes all sizes from newborn to adult. Hat is worked using Wortsed weight/ Aran (Size 4 Medium) yarn. Stitches used are single crochet, half double crochet, double crochet and slip stitch.
Gauge while working in the round is specified in the pattern.