Once your child out grows their forward-facing child seat, a booster seat is recommended to help ensure proper fit with adult safety belts.

Booster seats are designed to raise kids up so those adult sized safety belts fit the correct way. But now a new study out by the Insurance Institute for Highway Safety is warning parents that six kinds of booster seats are not recommended and asking parents to avoid them. Children aged four to eight in booster seats are 45% less likely to be injured in a crash than those using only seat belts.

Although the IIHS says booster seats have improved in the three years it has been testing them, it is concerned that those requiring parents to check the fit still outnumber the good ones. Of 83 seats tested, 41 got a "check fit" rating, and 31 were rated "best bets" or "good bets" by the IIHS.

Four booster seats made by Evenflo and two by Dorel's Safety 1st brand were rated so poorly the IIHS recommended consumers not use them. They are: the Evenflo Chase, Express, Generations 65 and Sightseer models and Safety 1st's All-in-One and Omega Elite.

If seat belts aren't positioned properly, children can hit parts of the vehicle in a crash and even be injured by the belts, which can slice into internal organs.

The IIHS also reported states that raised the requirements for booster seats to cover children through ages seven or eight had 17% fewer fatal or debilitating injuries to booster seat-aged children.

The IIHS singled out the Canadian company Harmony Juvenile Products as a "standout" in booster seat design because all five of its seats were "best bets." The first inflatable booster seat, the Bubblebum, also got the top rating.

"Evenflo Express" Evenflo Express Available in highback only Tested model: #3292198

"Evenflo Generations 65" Evenflo Generations 65 Available in highback only Tested model: #37611060

"Evenflo Sightseer" Evenflo Sightseer Available in highback only Tested model: #2692198

"Safety 1st All-in-One" Safety 1st All-in-One Available in highback only Tested model: #22178

"Safety 1st Alpha Omega Elite" Dorel Juvenile Group has issued a safety recall on this convertible model manufactured from May 1, 2008 through April 30, 2009 involving the harness locking and release button. Registered owners will receive a free remedy kit; all others should email DJG at harnessadjustment@djgusa.com or call 1-866-623-3139.