BubbleBum travel booster seatWeb: BubbleBum.us

Booster type: Backless

Weight: 40 lbs. to 100 lbs. (kids over age 4)

Price: $22 to $30

IIHS rating: Best Bet.

NHTSA: Four out of five stars.

Pros: Small and lightweight. Deflates and rolls up into carry bag for travel. Good for three-across situation.

Cons: Unstable, wobbly to sit on. Not comfortable for a long car ride.

Comments: BubbleBum is an inflatable, backless booster seat invented by a certified car seat tech from Northern Ireland (it’s been available in the UK for quite a while). The idea was to have an easy-to-carry booster seat option for travel, rental cars, etc. But it’s also a great option if you live in a place like New York and need a portable option for Uber.

Another plus: it’s cheap (about $30). But does it work well? Car seat techs report that the BubbleBum does provide good lap and shoulder belt fit (the IIHS gave it a “Best Bet” rating). The seat belt is threaded through a lap belt positioner, which keeps the belt in the proper position.

Critics note it can be confusing to use the positioner at first. Techs recommend threading the seat belt through the positioner after you have buckled your child into the seat to get a tighter fit—it’s hard for a child to do this by herself. That means you (the parent) will be doing this and that isn’t fun in a hot rental car for frequent stops.

FYI: BumbleBum revised the belt positioner in mid 2015 to be easier to use; most of the complaints we see on the Bumblebum are for the old adjuster.

Also: keep in mind the BumbleBum is a small seat and doesn’t provide much thigh support. So the BumbleBum isn’t going to be comfortable for long-term use. On the plus side, however, the small size of the seat makes it possible to use it in a three-across situation.

Most readers are happy with the Bumblebum, despite these drawbacks. We like the BumbleBum for it’s portability, price and safety. When used for short-term situations and travel, it’s a great option. Rating: A