Boston Red Sox Kids 47 Clean-Up - Green Monster Cross Bats  Kids green Red Sox Fenway Park cotton garment washed hat with embroidered logo on the front and adjustable strap in the back. Generally we say Inf - Newborn to 2 years, Tod - 2 years to 4 years, Kids - 4 years to 6 years, Youth - 6 years to 8 years, 8 years and up should move to adult sized hats.