The Thermotech Toddlers' Performance Base Layer Set offers the midweight warmth, comfort and moisture management that your little one needs. This set includes a long sleeve baselayer top as well as baselayer bottoms which are 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. Both pieces are knit with ACCLIMATE® Dry polyester fibers that transport moisture away from the skin, keeping your little one dry, warm and comfortable while their odor blocking technology enhances freshness and odor control. Keep your little one cozy and happy this winter with the Thermotech Toddlers' Performance Base Layer Set!