This bundle includes britax baby safe i size car seat britax baby safe i size flex base britax baby safe i size car seat baby safe i size is the first britax infant carrier that conforms to the new car seat regulation ece r129 i size the seat provides safety and comfort for newborns up to 15 months adjusting and protecting your child as they develop and grow to 83 cm in height features newborn insert is especially designed to give extra support to small babies the included newborn insert