With these Uppababy Vista lower adaptors you can allow a second carry cot to be fitted to the chassis when used in conjunction with the Upper Adaptors to make the pushchair suitable for Twins. Alternatively, they can be used to fit the carry cot to the lower part of the chassis in conjunction with the seat unit and Upper Adaptors to make the Vista suitable for a new born and toddler. Please note: These adaptors are required for the following configurations: carrycot and toddler seat, 2 carrycots.