The Woombie Grow With Me is a 5 stage swaddle + wearable blanket that covers your growing baby from 0-9 months with a BONUS extended length to reach up to 18 months, covering all stages of healthy and successful sleep for your baby! Stage One: Swaddle. -- (0-3 Months/5-13 lbs). For babies 20+ inches long. Place baby inside of swaddle and simply zip from the bottom all the way to the top. Stage Two: Swaddle+ -- (2-4 Months/12-16 lbs). For babies 22+ inches long. Unzip swaddle 2/3 way to opposite bottom corner. Expands 1.25" and adds 4" in length. Stage Three: Expanded Swaddle -- (3-6 Months/14-19 lbs). For babies 24+ inches long. Fully unzip swaddle with babies arms remaining inside for the same comforting touch. Swaddle increases over 3" in width and 4-8" in length. Stage Four: Wearable Blanket -- (6-9 Months/20-25 lbs). For babies 24+ inches long. With swaddle fully unzipped, open arm snaps on the sides to allow for "arms-free" sleep, transforming the swaddle into a warm and cozy wearable blanket. BONUS Stage Five: XL Wearable Blanket -- (9-18 Months/20-28 lbs). For babies 27-33 inches long. Fabric on the bottom of the swaddle lengthens to grow with your baby!.