Helly Hansen Warm Flow High Neck 1/2 Zip Womens Running Top Merino Wool Lifa Flow - For super quick drying next to skin, Lifa Flow quickly moves away moisture to keep you dry and comfortable. Pure merino wool - A lightweight wool with high thermal properties. Flatlock Stitching - Eliminates Skin irritation and potential chafing. Half Zip - Allows the wearer to determine their own level of ventilation.