From the North American Schachenmayr website:
Four bright shades of Schachenmayr original Boston are alternated in rounds of half double crochet to make a bright, fun hat - also perfect for odds and ends from your Boston yarn stash!

This is a FREE pattern available to all visitors of the North American Schachenmayr website.

Finished dimensions:
Head circumference: 22 inches (56 cm)
Height of hat: 8¼ inches (21 cm)

Yarn Information:
A - #00171 neon green
1 skein
60 yards

B - #00026 pumpkin
1 skein
60 yards

C - #00121 neon yellow
1 skein
60 yards

D - #00031 claret
1 skein
60 yards