SHERPA ADVENTURE GEAR Men's Vayu Zip Tee Primaloft Silver Performance Yarn Merino Wool Blend-50% Merino Wool Yarn, 50% Primaloft Yarn Imported Low-profile, flat seams are sewn with a microdenier yarn for softness against the skin; they are also reversed out to minimize chafing The hybrid fabric blends very thin PrimaLoft yarns with Merino wool yarns, resulting in a knit that outperforms 100% wool This hybrid fabric dries 20% faster than wool alone, absorbs less moisture, and is better at regulating the wearer's body temperature Ultra-fine PrimaLoft fibers are half the size of cashmere fibers, which makes the blended knit feel much softer than 100% wool knits Sleeve construction places seams away from shoulder tops where they could chafe under pack straps