My infant, toddler, and grade-school children fall asleep on the road because the Diono car seats are so cushy, you’d never know it has a steel alloy frame and aluminum reinforced side walls. The Radian rXT can accommodate all four of my kids, thanks to its multiple modes. When the chair is rear-facing, it can support a child up to 45 pounds. When the chair is forward-facing with a harness, it can support up to 80 pounds. And finally, there’s the booster mode, for children weighing up to 120 pounds. Best of all, it folds flat, packs into a carrying case, and fits three across in most mid-size vehicles and on airline seats too.