“Combination” car seats refer to seats which can be used as a forward-facing car seat (with the 5-point harness), and then transform into a belt-positioning booster. Combination seats will have designated height and weight limits for each mode, so read the instructions carefully to determine which mode is recommended for your child. Be sure to follow the installation instructions for the specific mode which you intend to use.

“Three-in-one” car seats can convert between three different modes. Usually this refers to a seat that has rear-facing, forward-facing, and high-back booster modes. Sometimes, however, the term is used for a seat that can be used in forward-facing, high-back booster, and backless booster modes, so read the labels carefully. These types of seats are a great option for parents who want to get a lot of mileage out of a single purchase. However, you should be aware of your car seat’s expiration date (usually 6-10 years beyond date of manufacture) and never use it beyond that point. Read the instructions carefully to determine which mode is the best for your child. Three-in-one child seats will feature different installation instructions for each mode. Make sure that you are using the correct base settings, shoulder harness slots, and seat belt route for the mode in which you wish to install it.

A “high-back” booster is the best option for a newly-transitioned child who has never used a booster seat before. This type of booster has a back which usually holds and positions the shoulder portion of the seat belt properly over the child’s shoulder (keeping it away from his neck). Some children like high-back boosters because they have side wings which make the child feel more secure. Many parents and safety advocates like them because they make it harder for the child to squirm away from the proper seat belt position! Like all boosters, this type should only be used in a seating position which has a lap and shoulder belt, never just a lap belt alone.

“Backless” boosters do not have the back portion, so the shoulder portion of the belt is more free to move. These types of boosters can be very safe, but only if the child understands how to sit properly in one and does not allow the shoulder belt to move to improper positions. If a child demonstrates that he is mature enough to use a backless booster properly, then a backless booster is a fine safety option. However, backless boosters should only be used in vehicle seating positions which have a head rest to properly restrain your child’s head from behind. Make sure to adjust the head rest to the proper height for your child. Like all boosters, this type should only be used in a seating position which has a lap and shoulder belt, never just a lap belt alone.