Size Small (Sizing is measured from right to left seam)
Shoulders: 16" (Right seam to left seam)
Chest: 21" (Right seam to left seam)

Size Medium (Sizing is measured from right to left seam)
Shoulders: 16.5" (Right seam to left seam)
Chest: 21.5" (Right seam to left seam)

Size Large (Sizing is measured from right to left seam)
Shoulders: 18.5" (Right seam to left seam)
Chest: 22.5" (Right seam to left seam)

Size XLarge (Sizing is measured from right to left seam)
Shoulders: 19.5" (Right seam to left seam)
Chest: 22.5" (Right seam to left seam)