The Baby Merlin Magic Sleepsuit size 6-9 months (18-21 lbs). It is the original, patented swaddle transition product that helps transition babies from the swaddle by providing them with a cozy, secure feeling. It was created by a mother of four who is a pediatric physical therapist to improve the quality and duration of her babies' sleep. - First and only patented swaddle transition product - Designed for back sleeping in the crib at the recommended room temperature for babies - Invented by a mother of four and pediatric physical therapist - Helps establish good sleep habits and patterns - Provides parents peace of mind that their baby is getting adequate rest necessary for appropriate growth and development