Crafted from an ultralight 150gsm blend of 65% polyester and 35% bamboo rayon , it delivers the perfect balance of next-to-skin softness, breathability, and moisture-wicking performance . Whether you're glassing ridgelines, hiking into a high basin, or working a hopper pattern on the river, the Wickiup keeps you cool, dry, and comfortable when it counts. Wear it solo during warm summer days or as your next-to-skin layer when the temperatures drop—the Wickiup is built to move with you all season long. Why This Fabric? Polyester provides the durability, stretch, and fast-drying power you expect from a technical piece. Rayon—made from bamboo—adds a natural, silky feel and breathability that outperforms typical synthetics. The result? A base layer that works as hard as you do and feels great doing it.