The Car Seat Adaptor for the City Select allows you to use your Car Seat with your City Select stroller. It is designed to fit several popular car seat models including those by Maxi Cosi, Peg Perego, Britax, Graco and Evenflo. (To configure for two car seats, the second seat for the stroller or a set of double adaptor brackets must be purchased in advance as these brackets are required to support the second car seat.)