The XTM Merino Womens Thermal Top is made from 100% fine Australian Merino wool, and at 230 gms is the perfect thermal base layer. With thermo-regulating properties, keeping you cool in warmer climates and warm in colder climates, this Merino thermal top is extremely breathable, non-itch, and the perfect companion to the XTM Merino Womens Thermal Pant 2019.