Great woolino sleep sack for an older toddler or preschooler feels like a generous 3-4t size. Super comfy, lots of life left in this one! FEATURES & BENEFITS Premium Natural Fabrics: silky soft Australian merino wool lining & organic cotton outer Merino wool regulates body temperature unlike any other fiber, keeping baby warm when it's cold and cool when it's hot Can be used in all 4 seasons - suitable for room temperatures 63-77F (17-25C) Foot openings allow child to sleep with feet out Unzips from bottom for easy diaper changes Zipper-pull guards to protect child's skin Nursery thermometer with dressing guide included