Keep your child harnessed longer Help keep your child harnessed as long as you can and if you can do that without buying a procession of car seats, even better! The new Nautilus™ 3-in-1 Car Seat is the only forward-facing car seat your child will need. It helps keep him safe in a 5-point harness longer than most car seats – all the way up to 65 lbs. Later, the seat converts to a highback booster then backless booster, for comfortable, custom protection up to 100 lbs. Extensive crash testing and a steel-reinforced structure give parents peace of mind, while the height adjusting head support and extra-comfy seat with wide armrests, cup holder and side storage help your precious passenger relax and enjoy the ride.