What Our Gearhead(R) Experts Are Saying:"This shirt is a game-changer for full-sun days. The ActiveIce treatment is legit-I actually feel cooler as I heat up. It dries super fast and has a smooth fit that doesn't ride up or chafe under a pack. I bring it on every summer trip."We don't back down from heat-we dress smart for it. The Outdoor Research ActiveIce Spectrum Sun T-Shirt is our top pick for long days in sun-scorched environments, offering cooling performance, UPF 50+ protection, and moisture-wicking power all in one sleek package. Whether we're charging up ridgelines or grinding out desert miles, this shirt helps us keep our cool. Powered by thermo-regulating ActiveIce(TM) technology, the fabric actively cools as we sweat-keeping us comfortable even when the sun is relentless. The recycled polyester blend stretches with us and dries quickly, while the chafe-free seams and dynamic reach design allow for smooth movement under packs or while scrambling. It's built for high output in high heat.