100% 260gram or 200gram 18.5 micron extra fine merino wool base layer for high loft insulation and moisture management. Ergonomic cuff with thumb loops, next to skin base layer, breathable pure merino wool fabric, lightweight and warm, best for hunting. Merino wool is silent, thermo regulating, and odor free, making the base layer a must-have piece for any serious hunter looking for an edge in the backcountry or treestand. Care Instructions: This 100% pure merino wool. Do Not Bleach, 30 Very Mild, Do Not Tumble Dry, Iron Max Heat 110, Do Not Dry Clean, Wash with Similar Colors. Because it was made in the mountains rather than in a petrochemical laboratory. It's naturally renewable, recyclable.