The Stokke® Stokke® Crusi™ can be fitted with a combination of the Carry Cot and Sibling Seat, the regular seat and Sibling Seat, or a combination of either the Stokke® iZi Sleep™ or Stokke® iZi Go™ car seat and the Sibling Seat . It is not possible to fit the Stokke® Crusi™ with 2 Sibling Seats.