The “Best Bet” boosters, which included the EvenFlo Symphony 65 e3 and the Recaro ProBOOSTER, were those that achieved the best seat belt fit. This means that the shoulder belt stretched directly across the shoulder and the lap belt laid flat against the thighs, rather than against the abdomen.
Retailers should also know that the IIHS tested every function of each booster seat. This means models might have received two different ratings for each function. For example, the Cosco Pronto is a best bet when used in the highback mode, but the IIHS recommends that the fit be checked when it is used as a backless booster.