The Mountain Warehouse Men's Merino II Base Layer Top is a performance-oriented garment, crafted from a blend of 80% Merino Wool and 20% Polyester. 80% merino wool, 20% polyester Fabric: performance Design: plain Fastening: half zip Neckline: high-neck Sleeve-type: long-sleeved Fabric technology: anti-bacterial, breathable, lightweight, moisture wicking XXS, XS: 33 in S: 37 in M: 40 in L: 43 in XL: 46 in XXL: 49 in 3XL: 53 in 4XL: 56 in