The Big Agnes Kids' Duster 15 Degree Sleeping Bag is an adjustable sleeping bag for kids to juniors. The polyester ripstop shell fabric is tough for plenty of seasons of growing with your kid. The soft interior lining is just right for cozying up to sleep. Using the loop and closure system, when the child is small, it brings the insulation in to eliminate cold spots, then expands as they grow. When it's time to pass it onto the next kid, adjust it all over again.