The Versatile Convertible For Infants To Toddlers. When your baby grows too big for his infant seat, but is too small to face forward, this 'in between' car seat is just right. The American Academy of Pediatricians recommends your child ride rear-facing as long as comfortably possible - at least until 20 lbs AND one year of age. The ComfortSport Convertible Car Seat can be used rear-facing up to 30 lbs then turns forward-facing for use as a toddler seat up to 40 lbs.