because the bottom harness slots are often above the shoulders of most newborns. A seat with low bottom harness slots can be used if it is desired to use a convertible from birth. Rear-facing weight limits range from depending on the manufacturer and country of origin. Forward-facing limits range from depending on the seat model and the manufacturer and country of origin. Most convertible seats in the U.S. have at least a rear-facing weight limit, most now to go to , some and a few . The American Academy of Pediatrics (AAP) recommends that children remain rear-facing until they outgrow their convertible seat, regardless of how old they are. Children can remain in a rear-facing seat until they have either outgrown the weight limit for their seat, or the top of their head is within of the top of the shell of the car seat. Group 1 A permanent fixture in the car using an adult seat belt to hold it in place and a five-point baby harness to hold the infant. Position: Sitting, recommended rear-facing but forward-facing is legal, no airbag (with the exception of curtain airbags). Recommended weight: 9 kg to 18 kg (20 lb to 40 lb) Approximate age: 9 months to 4 years (Although older children can fit too sometimes) It is recommended that children sit rear-facing for as long as possible. In Scandinavian countries, for example, children sit rear-facing until around 4 years old. Rear-facing car seats are significantly safer in frontal collisions, which are the most likely to cause severe injury and death. Rear-facing group 1 car seats are becoming more widespread but are still difficult to source in many countries. Group 2 A larger seat than the Group 1 design. These seats use an adult seat belt to hold the child in place. Position: Sitting, forward-facing or rear-facing (make sure the seat is certified for up to Recommended weight: 15 kg to 25 kg (33 lb to 55 lb) Approximate age: 4 to 6 years (Although older children can sometimes fit) Group 3 Also known as booster seats, these position the child so that the adult seat belt is held in the correct position for safety and comfort. Position: Sitting, forward-facing Recommended weight: 22 kg to 36 kg (48 lb to 76 lb) Approximate age: 4 to 10, and above if the child is not yet Booster seats Booster seats are recommended for