PATAGONIA. 52980REYE. SHORT SLEEVED MAINSTAY TEE. RESIN YELLOW. This go-to tee may have a hard time making it into your laundry basket. Our lightest-weight top is made from a cool-wearing blend of 60 percent organic cotton 40 percent polyester slub-knit jersey fabric that moves air and dries quickly. It has a classic T-shirt silhouette with left-chest patch pocket for keys or lip balm. Straight hem falls to hip.