Built with Smartwool's lightest weight Merino wool wrapped around a nylon core, the Women's All Season Long Sleeve 1/4 Zip Baselayer is highly durable while still being comfortable. This composition allows for 100% of the Merino wool to be next to the skin for unbeatable cosiness. Merino 150 is soft, breathable and lightweight; not only is it comfortable, but it also allows sweat to move away from the body keeping you dry. The baselayer offers stretch and a full range of motion while being flattering on all body types.Slim fit - flattering on all body shapes, follows the contours of the bodyLightest weight Merino jersey with a nylon core - increases durability while still keeping 100% Merino wool next to skin for comfortMerino 150 - breathable, soft, lightweight fabric offers next-to-skin comfort, moves sweat away from the body, and acts as a versatile performance layer for warmer conditionsStretch merrow stitching designed to elevate comfort, range of motion, and fitPrincess seams on front and back panels designed for figure-flattering fit8.25" (21 cm) center-front zipper with semi-locking sliderMaterial: 88% Merino Wool, 12% Nylon (exclusive of decoration)Colour: Light Grey