There are 4 stages of child restraint usage: rear facing , forward facing, belt positioning and seat belts. The type of seat you need will depend on your child’s age and size. Others may not but we include the prenatal stage as the child in the womb needs special attention and protection while in the car as well. When they are turned forward facing the body is being restrained by the harness strap and the neck and head are unrestrained. The child’s body is dependent on the strength of his spine to handle the stress of a crash.