King's built the merinos to be the foundation and next to skin layers of your XKG hunting system. Construction consists of 17.5 micron 100% Merino wool that weighs 150 grams which functions in any condition - keeping you cool in the heat with its breathability and warm in the cold with its tightly sewn fine wool fibers. The Merino 150 ¼ Zip is assembled with a no-itch flatlock seam construction. It's material is ultra-breathable, and moisture-wicking. With its natural fibers, it's also excellent at controlling odor.