No gauge given. No specific yarn/needle size recommended - just that needle size should be appropriate for the chosen yarn. Calls for a circular and a set of dpns in the same size. Discussion in other forum posts suggests DK or worsted weight yarn would be best for this pattern.

Designer’s note from pattern:
Typically, if the hat I am knitting fits my head, it will fit the heads of most people unless they are unusually large or small people. Before you begin, you should probably measure and check your gauge to be sure that you cast on the right number. For this pattern, use multiples of six. The number I usually use is 90. That is the number of stitches that I will use for the instructions. If you have problems with adjusting this number, please let me know.

Also available in the Knitting Help Forum