UPPAbaby Vista allows for multiple second seat configurations. The Lower Adapters allow you to attach a Bassinet, Aria Infant Car Seat, Mesa Infant Car Seat, or RumbleSeat V3 to the Vista as the secondary seat. Large hubs ensure quick, no-tool attachment Color coded dot indicators to ensure proper installment Stroller folds with the adapters on Easy open and close mechanism with closure lock for ease of mind New audible “click” for closure for parent peace of mind and security New Red door to notify parent to close door fully Larger hubs and adapters ensure quick and easy attachment and removal Compatible with Bassinet, RumbleSeat V3, Mesa and Aria Infant Car Seats (not included) Supplier Code: 0901-VLA-NA Material: Plastic Care Instructions: Spot clean with a damp cloth Dimensions (in): 6 x 3 x 11.5 (15.2 x 7.6 x 29.2 cm) Note: RumbleSeat V3 comes with included Lower Adapters