bluesign-Approved Materials with Thermoregulating ActiveIce for Sunny Days The ActiveIce Spectrum Sun Long Sleeve Tee is built with thermoregulating ActiveIce technology and bluesign approved materials, perfect for keeping body temperature in check while hiking, backpacking, climbing, or setting up camp. This tee is built with an ultra-comfortable, breathable, and quick-drying polyester blend treated with our proprietary ActiveIce technology. ActiveIce reacts to your body's rising temperature by cooling down your core, keeping you in the sweet spot longer while pushing the tempo or working hard. The chafe-free design, built-in stretch, and UPF 50+ are welcome essentials for long days spent under the sun, while thumb holes at the ends of the sleeves deliver sun protection that stays in place while reaching for the next hold or setting the pace on the trail. Purpose-built for staying cool while spending long days in the mountains under the sun, the ActiveIce Spectrum Sun Long Sleeve Tee is a warm-weather staple for every outdoor enthusiast.