Royal Robbins Coolmax Extreme Expedition L/S Shirt - Men's - 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, punctures and tears. Royal Robbins Extreme Expedition L/S Shirt Features Dri X-treme? mesh lined vented yokes Hidden button down collar Hook & loop secure document pockets Zip secure front pockets Underarm gussets Button roll-up sleeves Materials 2.9 oz., 100% Coolmax? Extreme Polyester