When babies are 0-3 months, they have limited hip mobility and teeny little legs that cannot straddle the panel of the TwinGo Orginial Carrier. The TwinGo Infant Insert allows baby to sit comfortably in the carrier as early as 7lbs in the front position. This accessory is not intended for the back carry or hip carry positions. Once baby is 3-4 months old, they can comfortably straddle the carrier without the Infant Insert. Features: When do I use the Infant Insert? Use the Infant Insert to support newborns starting at 7 lbs (3.2 kg) and up to the developmental stage when your baby’s legs can naturally spread to straddle the panel of the TwinGo Carrier. How do I use the Infant Insert? Before placing your baby in the carrier, slide the tail of the Infant Insert directly into the waistband; the label on the Infant Insert will touch your stomach. Bring your baby to your chest and place your baby’s bottom on top of the round cushion. If your baby’s hips have limited motion, he will sit in the fetal position. If your baby’s hips have more advanced motion, he will spread his legs to straddle the cushion. Your Infant Insert will come with an instruction manual to illustrate these steps. What if my baby needs more head or neck support? If your baby has a long torso and requires additional neck and head support, you can roll the Sleep Hood behind your baby’s neck and secure it in place with the extension straps. Made of soft foam. Cover with 100% black cotton fabric