PREMIUM FABRICS FOR BEST COMFORT - The award-winning 4 Season® Ultimate Baby Sleep Bag keeps your baby at a perfect temperature throughout the night, year-round. That means there’s no need to worry about which weight sleeping sack to use, or whether your baby will be too hot or cold while sleeping – they’ll always be just right! SAFER, BETTER, AND LONGER SLEEP - Made with super-fine and supremely breathable merino wool, it helps keep your baby warm when it’s cold and cool when it’s warm. That temperature regulation means that your baby will sleep comfortably throughout the night– and that means a better night's sleep for you too. The cuddly-soft organic cotton outer adds to the comfort as it's perfect for the most delicate skin. THE ONLY SLEEP BAG YOU NEED – With a universal size that fits babies from 0 months to 6 months, there is no need to worry about buying different sleeping bags as your little one grows or as the seasons change. You only need one Woolino sleep bag, right up until your baby turns two!