Our sleep bags are designed to make sleep safer and more comfortable for your baby. The lightweight and breathable cotton muslin helps prevent overheating and allows baby to move naturally. Included are parent-loving features like a two-way zipper for easy nighttime diaper changes, and machine washable cotton muslin that gets softer with every wash. Babies come in all shapes and sizes. Please reference our size chart to help you find the proper size for your baby. Size Baby Weight Baby Height Baby Age Medium 16-24 lbs 26"-30" 6-12 m