Bubble Bum - inflatable car booster seat
This is a wonderful alternative to a regular booster seat for children who can sit in one. When deflated, it folds in half and can be stored in the included bag.
http://www.amazon.com/BubbleBum-Car-...0943464&sr=8-1
It is also rated as a "Best Bet" by the IIHS.
http://www.iihs.org/iihs/ratings/chi...ters/best-bets