Fabric: 100% cotton. Filling: rice or flaxseed. Size: 4.5x4.5 inches. Care: spot clean only. Packaging: clear cellophane bag, sticker label with instructions. Hot therapy: microwave in 10 second increments until warm. Please, always monitor while microwaving and do a touch test before placing the pack on skin. Cold therapy: keep in your freezer in a sealed bag for at least an hour before use. Thank you for supporting my business!