From SNOO, this swaddle features: SNOO Sack was specially designed to be used in SNOO Smart Sleeper to help babies sleep safer, longer, and happier! And because SNOO Sack was created by world-renowned pediatrician Dr. Harvey Karp, you can trust that every detail was designed with baby safety and parent sanity in mind! Extra-quiet Velcro Breathable mesh at shoulders and legs to reduce risky overheating SNOO Sack is an all-seasons wrap that keeps babies cool & comfy with a Thermal Overall Grade (TOG) rating of 0.5 Special inner arm bands and leg flap keep Baby snug all night Snaps at shoulders let you swaddle with one or both arms out Speedy Two-Way Zipper - Opens from top or bottom for smoother diaper changes Prevents Risky Rolling - Patented wings attach to SNOO to keep Baby on the back International Hip Dysplasia Institute approved Small: 5-12 lbs. Medium: 12-18 lbs. Swaddle Length: Small 20.5 inches, Medium 23 inches *Please Note: Don't worry if your baby's feet can touch the bottom of the sack. That keeps the legs slightly bent, which aids in developing hips. 100% Organic cotton/elastane. Trim: Polyester Machine wash/tumble dry Imported.