Generic Error - gracobaby Booster Car Seats Booster Car Seats. As your child grows, they won't need a harnessed car seat, but they can always use a boost. Graco's forward-facing booster seats meet or exceed all US testing standards, helping properly fit your big kid to your vehicle’s seat belt. From 30 lbs, up to 120 lbs. Nautilus® 65 3-in-1 Harness Booster Car Seat | gracobaby This 3-in-1, side-impact tested car seat keeps your toddler harnessed from 22-65 lb, then provides versatility and longevity as a booster from 30-100 lbs.