This kids' base-layer set is made from a super soft Merino wool-Tencel® material. It helps regulate your little one's temperature whatever the time of year. The hard-wearing fabric stands up to the washing machine well and feels comfortable against the skin thanks to the soft, flat seams. The stretchy rib knit lends a snug fit but still allows for plenty of movement. This kids' thermal base layer is specially made for getting active.