Abstract: An apparatus for seating a child in a vehicle may include a seat, a backrest coupled to the seat at an angle, and an upper support movably coupled to the backrest. The upper support is configured to move relative to the backrest between an expanded configuration and a collapsed configuration. The upper support may be non-load bearing. The apparatus may further include a rethread harness system. A method of adjusting a children's car seat may include removing a locking component from a first receiving loop. The method may further include sliding a non-load bearing upper support along a backrest of the children's car seat. The method may further include inserting the locking component into a second receiving loop.