Cleveland Cavaliers Climalite Youth Long Sleeve Navy Blue Shirt Boys 8-20 100% Polyester Please note sizing tends to run SMALLER than average sizing. Youth Sizing 100% Polyester Performance Tee. Please note measurements to find the correct sizes Measurements Youth 8 Small 15 inches Width pit to pit, 22 inches top to bottom 10-12 Medium 16 inches Width pit to pit, 23 inches top to bottom 14-16 Large 18 inches Width pit to pit, 25 inches top to bottom 18 XL 19 inches Width pit to pit, 25 inches top to bottom