The Smartwool Women's Merino 250 Base Layer Top is a premium synthetic base layer top made with high-quality merino wool. Merino wool is known for its exceptional warmth, moisture-wicking properties, and odor resistance. This top features a 100% merino wool construction, providing superior insulation and breathability. The flatlock seams prevent chafing and ensure a comfortable fit. Whether you are skiing, hiking, or simply enjoying the outdoors, this top will keep you warm and comfortable. With its luxurious feel and excellent performance, it is no surprise that it is one of the most wished-for women's synthetic base layer tops on Amazon.