When the first chilly mornings of fall arrive, count on the midweight warmth of the Core Merino 220 Half-Zip. It features a double-layer merino wool blend that regulates temperature to keep you comfortable from mild early-season afternoons through cold snaps in late fall. Merino wool is also naturally odor-resistant to help keep your scent under wraps, and our ArmorSpun merino wool is reinforced with nylon to help it last season after season.