Spreadshirt Darwin I Think Evolutionary Tree Men's T-Shirt Designed and printed in the USA. This awesomely nerdy design features Darwin's sketch of the evolutionary tree of life. Makes a perfect gift for all who are studying biology or other natural sciences. Relaxed, tailored and ultra-comfortable short-sleeve t-shirt. You'll love the way you look in this durable, reliable classic. 100% pre-shrunk, heavyweight cotton (except for heathered colors); Fabric weight 5.0 oz. For best results and to maximize durability machine wash cold, inside out and tumble dry on low heat. Official sizing (width x length measured in inches): S (18" x 28") | M (19.5" x 29") | L (22" x 30") | XL 24" x 31") | XXL (26" x 32") | 3XL (27.5" x 32.5") | 4XL (34.5" x 29") | 5XL (31" x 35") | 6XL (33" x 37.5").