this patent pending, fastener-free, no over-the-head design makes baby changes easier than ever. You simply wrap the winged fabric across baby, inserting arms and legs through corresponding sleeves, and voila! Baby is dressed. No frustrating fasteners to match up. No noisy velcro to wake baby. No zippers to pierce baby's precious skin. the best part? it's reversible. Brushed 96% Polyester, 4% Spandex. Snuggly soft. Four-way stretch. Sizing by weight is recommended.