Published by at 03/08/2026 Outdoor Research Alpine Onset Merino 150 Half Zip in Black Heather. This high-performance base layer is crafted from a lightweight merino wool blend, offering natural odor resistance and moisture-wicking properties for all-day comfort during outdoor activities. Designed with a half-zip neckline for easy ventilation and thumbhole cuffs to keep sleeves in place and hands warm. The raglan sleeves and flat-seam construction ensure a comfortable, chafe-free fit under packs or additional layers. Ideal for hiking, skiing, or any cool-weather adventure.