Boston Red Sox 47 Clean-Up - St. Pat's - Kelly Hat. Boston Red Sox St. Pats Kelly Green Hat. Red Sox kelly relaxed fit hat with a raised embroidery B logo and a shamrock on the back, the Classic look for St. Patrick's Day in Boston, or at JetBlue park. This hat is 100% garment washed cotton for a broken-in look and feel. This hat has a cloth adjustable strap and is one size fits all.