CafePress Union Jack Dog T-Shirt Size Info:Small (10 length, up to 10 lbs), Medium (12 length, 12-25 lbs) Large (15.5 length, 26-40 lbs), XL (17.5 length, 41-60 lbs), 2XL (20 length, 61-80 lbs) Made of 100% ring spun cotton. 5.8oz. 1x1 rib. Black ringer accent on sleeves and collar.