Bella Infant"s 4.5 oz. Long-Sleeve Thermal One-Piece Onesie: 60% cotton, 40% polyester; 40-singles combed ringspun cotton; custom fit thermal with retro ribbed neckband & leg opening; soft mini waffle thermal with a delicate appearance; great when layered with short-sleeve styles for extra warmth; laundered for softness and minimal shrinkage