Reversible 100% Cotton Sleeping Bag. Outer fabric is cotton poplin/flannel. The inner fabric is a solid color 4-layer multi muslin fabric. Our fabrics are 100% cotton, organic and Gots Certified. Thanks to its breathable structure, it will prevent your baby from sweating without harming their sensitive skin. You can choose it as sleeveless or with sleeves, depending on the temperature of your home. *If the temperature of your house drops to 20 degrees, you can choose the long sleeve one. *If it is around 23-24 degrees, you should choose the sleeveless one. Machine wash at 30 degrees. Dry at low temperature or by hanging. Since Multi muslin has a fast drying feature, it will be easy for you to dry it.