Made with a premium polyester/rayon blend and boasting three layers of buttery knit fabric for superior softness and stretch, this sleep bag is designed with baby's comfort in mind. It is warm and cozy with a 1.25 Thermal Overall Grade (TOG) rating ideal for room temperatures between 65-75 degrees F and a sleeveless design to offer the perfect amount of wamth for year-round use helping baby sleep through the night. The 0-6 month size is 26.5" long and 13" under the armpits and 18.5" at widest section and the 6-12 month is 28" wide, 14" under the armpits, and 19" at the widest section. The bag also has a tag-free neck and a convenient top-to-bottom zipper for easy on and off.