This is a sleep sack for sleeping. The size is 60, but it's a loose fit, so we used it until around 2 years old. (This may vary depending on your child's growth, so please consider it as a reference.) There are buttons on the shoulders and both sides, making it easy to put on even after your child is asleep. It's made of 6 layers of cotton, so it can be used from now until winter, excluding winter itself. I think it's perfect for preventing chills while sleeping. I washed it with baby detergent every time. We live in a new house and do not have pets. We also do not smoke. Thank you.