Also available on T-shirt

The Sizes and Dimensions are as Follows:

Small (6 - 8): Pit to Pit - 19.60", Length 26".
Medium (10 - 12): Pit to Pit - 21.5", Length - 27".
Large (14 - 16): Pit to Pit - 24", Length - 28".
Extra Large (18 - 20): Pit to Pit - 26", Length - 29".

Product Info:

No-pill 50% Cotton/50% Polyester, 9.3-oz., with double-needle stitching and double-needle cuffs.