Today’s contoured vehicle seats often tilt infant carriers back towards the rear of the seat, positioning infants at an incorrect angle. Forget rolled up towels. Sit Rite will not flatten during tightening and installation. The dense foam construction adds firm, lateral support to the vehicle seat to help discourage sideways tipping. Sit Rite can be used with most rear-facing child safety seats. It cannot be used with Diono car seats. Crash tested.