Sizes for kids to adults. This fits perfectly for that great helmet hat you have been looking for! You would pay quite a bit of money for department store knit helmets. Why waste the money! You can knit your own with this very easy pattern! We used scraps of yarn to make it more colorful, but you can come up with your own color combination. Uses worsted weight yarns, and a 16 “ circular needle, US# 8.