Our warmest all synthetic base layer, the Lune Half Zip is made from a smooth and shiny polyester material with 4-way stretch. A brushed inside creates the softest feel and helps to wick-moisture away from the body. The sleeves have a unique, one-panel construction as well as flatlock seams for ultimate comfort when active. The base layer fits slim, making it perfect for layering, and a front zip opening makes for fast ventilation.