What Our Gearhead® Experts Are Saying:“This is one of my favorite winter base layers. It’s super warm, breathable, and layers like a dream under my shell. The jacquard pattern stands out in a subtle way, and the half zip helps with quick ventilation when I’m working hard skinning uphill.”When the mercury drops and the snow starts falling, we reach for the Icebreaker Merino 260 Tech Vertex LS 1/2-Zip Top GRX1. Crafted with 100% merino wool in a heavier 260-weight knit, this alpine-ready base layer delivers serious warmth and breathability for long, cold days in the mountains. The sleek jacquard pattern echoes the lines and textures of glacial terrain—subtle, technical, and visually unique. The performance fit and smart construction elevate this layer even further. A gusseted underarm and offset seams allow for fluid movement without chafing, and the zip-neck design lets us vent heat on the fly. The drop-tail hem provides extra coverage on deep powder days or windy ridgelines, while the soft merino knit regulates body temperature to keep us comfortable whether we’re charging uphill or kicking back in the hut.