This pattern is made to fit an adult-sized head. You can use any size or type of yarn. You can even change stitch pattern. This pattern is highly customizable to how you want it to look.
Picture instructions are provided along with measurements so that no matter what yarn you use, your ear warmer will turn out to be the same size as mine.
I used scrap yarn for mine, so yardage is approximate. Hook size will depend on what size yarn you use.