An updated the fit for the Women's Classic Thermal Merino Base Layer 1/4 Zip to improve functionality while also enhancing aesthetics. As one of Smartwool's heaviest base layer tops and one of their best base layers for cold weather, this garment uses 100% responsibly sourced Merino wool, shoulder panels, and a flatlock seam construction to help prevent chafing as well as keep you comfortable and temperature regulated as you enjoy high-intensity skiing, hiking, running, and more.100% Merino Wool Slim fit is intended to follow the contours of the body 100% Merino wool fabric made with an interlock knit for enhanced comfort, breathability, thermoregulation and odor resistance Back body seam wraps to front for body-enhancing fit, Raglan sleeves 8" (20 cm) center-front zip with semi-locking slider Flatlock seam construction designed to minimize chafing Women's Smartwool Classic Thermal Merino Base Layer 1/4 Zip