Make every high effort outing smooth as butter with a long-sleeve layer that's worth its weight in sunscreen—minus the need for reapplication. This versatile piece holds its own solidly solo, providing UPF 50 coverage when the sun is glaring around every corner of singletrack and bouncing off every surface of rock and snow. And it plays well with others, too—providing a layering option that'll keep you running cool under an insulated jacket with built-in moisture wicking and anti-odor properties. Knowing UV increases 2% for every 1,000-foot gained, you'll be ready to earn some elevation in this soft-wearing, protective layer.