The Seat Extender Insert can be used with the Britax BABY CARRIER once your child no longer requires use of the infant insert. The Seat Extender Insert is a removable support that provides a wider seating area by cradling your baby’s bottom and thighs, which allows your child to wrap or splay their legs around your waist when facing inward through the entire use of the carrier. This supports a wide, spread squatting position for your child and enhanced longer-wearing comfort for you through balanced weight distribution.