100% Cotton 100% Organic Cotton, soft and smooth, not irritate baby's delicate skin. Size: Small suitable for height under 31.5", Large suitable for height under 39.4", X-Large suitable for height under 45.3". Open zipper for easy dressing and diaper changes. Zippered cuffs, exposing a small hand to facilitate the baby activities. Perfect design allows room for kicking and cannot be kicked off at night, prevents baby from catching cold and helps establish good sleep habits. Going out in a cart can keep the baby from the wind. Hand wash and Machine wash. Do not bleach, Do not dry clean.