The Nike Women's Pro Warm Base Layer Top is a top-rated choice for women's outdoor base layer tops. It is made with a blend of polyester and spandex, providing a comfortable and stretchy fit. The fabric is designed to wick away moisture and keep you dry during intense activities. The top also features a mock neck design for added warmth and a snug fit. With its lightweight and breathable construction, this base layer top is perfect for high-intensity outdoor activities like running, hiking, and skiing.