This felted ribbed cap retains the ribbing even after the felting. The brim is also doubled over to provide extra warmth for tender ears

This pattern should fit most adult head sizes, depending on how much one felts the cap. I originally designed and knit the hat for Mike, who has a 22” head circumference. If you felt it enough, it will likely fit a teen’s head as well, and be warmer and more water resistant to boot.

I put no gauge for two reasons. One, I don’t remember the gauge. Two, the gauge doesn’t matter that much since the work is felted. I would just suggest hand felting the cap in a sink little by little until it matches the size head you are looking for.