This soft and stretchy material comes with brushed fleece interior, providing maximum warmth without the bulkiness. The classic crew-neck, long-sleeves designs make this the perfect layering basics for the colder days. You get three colors of thermal top with this purchase. General sizing guide is Small (6 years), Medium (8 years), Large (10 years), X-Large (12 years). Material content is 55% Polyester, 35% Cotton, 10% Spandex. Machine wash, line dry. For better results, use laundry bag or hand wash.