2-24 months GUC - has wash wear Premium Natural Fabrics Silky-soft hypoallergenic merino wool lining and the finest organic cotton outer. 4 Season use Unlike other brand sleep sacks that come in either winter or summer weight/TOG rating, the Woolino 4 Season Sleep Bag can be used year-round. It’s suitable for room temperature 63-75F (17-24C). Because of merino’s unique ability to regulate body temperature, it helps keep your baby warm when it's cold and cool when it's hot. Grows with your baby It is designed to fit kids 2 to 4 years old. For smaller children, adjust the fit by closing the underarm snaps. Excellent value It saves you buying a different sleep bag every few months. It’s the only sleep bag your toddler will need, in winter or summer, for 2 years. Designed to be practical It features double shoulder snaps and a two-way side zipper, so you can open it completely flat for easy dressing without waking the baby! For easy nighttime diaper changes, you can open the bottom only. Zipper-pull guards protect baby's skin and discourage child from chewing on the zipper pull. Travel friendly A closable seatbelt opening allows for easy transfer between stroller, car seat, and crib, so you can keep your baby’s sleep routine intact while on the go. Replaces loose blankets Helps your child to stay covered through the night.