The car seats below are compatible with the BOB Revolution Flex Duallie double stroller using an adapter:

• Britax/BOB B-Safe 35, Chaperone, B-Safe, B-Safe 35 Elite with adapter
• Chicco KeyFit and KeyFit30 with adapter
• Graco SnugRide Click Connect 30, 30LX, 35, 35LX and 40; SnugRide Classic Connect, 30, 32, 35 (with adapter)

The BOB Revolution Flex Duallie fits only one car seat. It cannot be used with two car seats for twins.