« The 3.5 TOG Sleep Suit Sack is the perfect long-sleeve winter sleep suit to keep babies, toddlers and kids warm during sleep in room temperatures 57-70°F. The 3.5 TOG rating means that there is no need for additional blankets in the crib when using this product, making it a safe-sleep option. Parents can be assured the breathable GOTS certified Organic Cotton will help your child maintain an even temperature whilst sleeping, and prevent overheating. » Full description on website.