Mens/Unisex shirts are printed on American Apparel 2001 or Royal Apparel 5051 and Ladies shirts are printed on Bella "Favorite Tee" Ring-Spun Super Soft Jersey Knit (6004), color of Royal. 3XL and 4XL may be substituted with a different brand. Not sure what size you need? We have Always order up a size if in doubt.