When you want serious warmth and breathability, reach for the Sierra Long Sleeve Zip. A superior solution to synthetics, our RealFLEECE has recycled merino fiber wrapped around a nylon core, then brushed to maximize warmth and softness. With a hint of LYCRA, the Sierra fits like a charm and is built for performance, keeping out the cold when you’re hiking, skiing or sightseeing, but always breathable and resists odor day after day. Feel the difference and you’ll be a convert.