HOW TO CHOOSE A CAR SEAT
What is a convertible car seat?
Convertible refers to two modes of use—rear-facing for newborns and toddlers to forward-facing when height or weight requirements are met. Multiple recline and headrest settings in both modes keep your baby comfortable and secure. Time to graduate from the convertible when your child is 65 lbs. or 49 inches.
Convertible Car Seat Checklist
Transition smoothly from rear-facing to forward-facing with a car seat that converts Keep your little one rear-facing up to 40 lbs. Get one single car seat that will last from infant through preschool 
If you choose a convertible for your infant, keep in mind that it won't click into a stay-in-car base or strollers