Here's more info about the Diono RadianRXT:
The RadianRXT is a highly versatile car seat that could be the only seat you’ll ever need. It comfortably seats rear-facing children from 5-45 lbs, forward-facing children from 20-80 lbs in 5-point harness, then converts to a booster for children up to 120 lbs. It’s built for strength and safety with a steel alloy frame, reinforced sidewalls, adjustable head support and our patented SafeStop® energy absorbing harness. EPS foam surrounds the child's head and body to provide complete side impact protection. Our unique SuperLATCH system makes installation easy. The RadianRXT is NCAP crash tested, the industry benchmark for verifying child seat performance in severe accident conditions, and the onlycar seatrated for LATCH use with a child up to 80 lbs. The RadianRXT sits low on a vehicle seat for easy child boarding, features memory foam padding and infant support pillows. Expandable sides and a longer seat bottom provide extra room and comfort for your growing child. One cup holder is included, with the option to add up to 4 cup holders. In addition to all this versatility, it folds flat for travel and storage, has a 10 year life and offers amazing safety, comfort and convenience your child won’t outgrow.