Boys Thermal Underwear/ Base Layer Long Sleeve Top and Long Pants Set - Size M or fits 8/10 Soft, comfy and cosy, and keeps really warm even though it is not too thick. Perfect for layering in cooler temperatures. Material is 100% Polyester. Brand is Cuddl Duds. From manufacturer : • These Cuddl duds Boys Comfortech Stretch Poly 2 Piece Set has stretch for flexible comfort and is lightweight for everyday comfort and warmth without the bulk. • ClimateSmart Wicks away moisture and stays dry. • Comfortech Added stretch for enhanced fit and comfort. • Thumbholes on sleeves for easy layering. Tagless. • Functional fly. Worn less than 3 times before it was outgrown. In excellent used condition from a smoke free and pet free home.