There's no better material for technical layering pieces than merino wool. Full stop. Plenty of other fancy fabrics from laboratories make for excellent active garments, but warmth, breathability, moisture wicking properties, and plain old soft-on-the-skin comfort of merino remain unbeaten. The Kari Traa Løkke Half Zip Top is made of 100% merino wool, with a medium weight, flatlock seams, and a slim fit for maximum layerability in the resort and the backcountry.