SAE Founders T-Shirt6. 1 ounce 100% ring spun cotton Soft washed garment dyed fabric Twill label Relaxed fit Please see size chart: This is a lay flat measurement for the chest. If you're comparing it to a traditional circumference measurement, a close estimate would be to double the lay flat size. S M L XL 2XL 3XL 4XL Body Length 26 3 5 28 29 2 5 30 3 4 31 3 5 32 1 2 33 1 2 Chest Width (Laid Flat) 18 1 4 20 1 4 22 24 26 27 3 4 29 3 4