The Astroman Sun Shirt is our best-selling lightweight, stretchy, and durable fabric packed with the highest rating of UPF 50+ sun protection. Named after the legendary route in Yosemite Valley, the Astroman was built for exposed and rugged climbs, but works equally as well for hiking, paddling, backpacking, or any other activity when you're headed out in the blazing sun. FABRIC : bluesign® approved 85% nylon, 15% spandex WEIGHT : 6.1 oz/173 g