The Smartwool Men's Merino Sport 150 Quarter-Zip is a warm weather layer for outdoor adventure. Hike the trails in the early morning, take a run in the afternoon and even just chill come evening. This ultralight layer is versatile and durable thanks to a Merino Wool and polyester blend. It manages moisture, offers coverage from the sun and even takes the chill of on breezy days. Features of the Smartwool Men's Merino Sport 150 Quarter-Zip Fabric combines the moisture management, temperature regulation, and odor resistance of Merino with the durability and quick dry time of polyester Mesh in key Areas designed to increase breathability and comfort during strenuous activities Flatlock seam construction designed to minimize chafing 9in. (22 cm) Center front zipper with semi-locking slider Reflective elements for increased visibility in low light conditions Fabric Details Body: 56% Merino Wool, 44% Polyester Lower Back Panel/Underarm : 54% Merino Wool, 46% Polyester