The pack includes 2 car seat adaptors.
 
There are not many side by side twin pushchairs that can take 2 car seats but the Mountain Buggy Duet is certainly one of them.
 
The new Mountain Buggy Duet Car Seat adaptors will turn the Mountain Buggy Duet doubles into a twin travel system. Suitable for the Maxi Cosi or Besafe or Kiddy or Recaro car seats.Compatible with Mountain Buggy Protect, Phil & Teds Alpha, Cybex Aton and Maxi-Cosi Cabriofix and Pebble Car Seats.
Directly attach two infant car seats to the buggy frame to let babies sleep between car and buggy. 
2 x Car seat adaptors and Car Seats can be attached to this pushchair.
Fabric seats need to be removed on Duet if used for twins, but can be used with fabric in place for a single seat on a Duet.
Will take a baby up to the max weight of 9 kg - around 10 months.
Fits the Mountain Buggy Duet
One or two seats can be fitted
Please note this is only suitable for the Duet*
EN 1888:2005 Safety Approved