Description of Royal Robbins Extreme Expedition L/S Shirt This wrinkle-resistant, lightweight fabric with UPF 40+, incorporates special fibers that channel moisture away from the body to help keep wearers dry. Grid-like construction makes this fabric highly durable and resistant to abrasions, pnctures and tears. Features: Coolmax Extreme Expedition ripstop 2.9oz, 100% Coolmax Extreme polyester UPF 40+ Wrinkle resistant Dri X-treme mesh lined collar band and vented back yoke Hidden button down collar Hook & Loop secure document pockets Button roll-up sleeve tabs Zip secure front pockets Running gussets Traditional fit