This extra base for use with the Chicco KeyFit 30 Infant Car Seat is a must if you have more than one car in the family. When each car is outfitted with a base, you can simply snap the car seat in and out of any of them, making it easy to get on the road without worrying whether it's installed properly each time.* This infant car seat base can be used with the Chicco KeyFit and KeyFit 30 infant car seats.