The Thermotech Women's Performance Base Layer Top offers the midweight warmth, comfort and moisture management that you need in a base layer. This top is made from a two-layer performance polyester fabric connected back-to-back with an open space between the layers to trap and hold warm air. It is knit with ACCLIMATE® Dry polyester fibers that transport moisture away from the skin keeping you dry, warm and comfortable while its odor blocking technology enhances freshness and odor control. Stay active and cozy this winter with the Thermotech Women's Performance Base Layer Top!