How to attach the sibling adaptors to the Stokke® Crusi™ stroller - YouTube
Stokke Car Seat Adapter Reg $74.99 – Royal Diaperer
Amazon.com: Stokke Stroller Multi Car Seat Adapter, Black - Compatible with Select Maxi COSI, Nuna, Cybex & Clek Car Seats - for Stokke Trailz Terrain, Xplory 6 & Xplory X Strollers -