The Britax B-Safe and Britax Chaperone Car Seat Adapter is the easiest way to turn your stroller into a customized travel system. Attaching your Britax car seat to a Baby Jogger stroller has never been easier. You can even fold the stroller with the adapter attached, giving you the most versatile travel system available. This specific car seat adapter is compatible with single mounting bracket strollers, including the City Mini 3W, City Mini 4W, City Mini GT and the Summit X3. If this adapter is not working on the consumers stroller model, then this consumer must have either a City Select or City Premier, which has its own adapter because the mounting system is different or the consumer has a Vue, Vue Lite, City Mini Zip, which do not have adapters compatible with the Britax car seats.