The Smartwool Classic Thermal Merino Base Layer 1/4 Zip is amazing on so many levels. Hailed as one of the best materials for getting after it in cold weather, this quarter zip is cut from 100% Merino wool that is temperature-regulating, breathable and odor-resistant. A flatlock seam construction keeps you chafe-free so you’ll stay comfortable all day whether you're skiing, hiking or running. Details: 100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation and odor resistance Fit updated to improve functionality while enhancing aesthetics Shoulder panels eliminate top shoulder seamsFlatlock seam construction designed to minimize chafing10' (25 cm) center front zipper semi-locking slider