Travel system compatible means that our Primo Viaggio SIP 30-30 car seat (sold separately) attaches easily to the chassis for the convenience of moving baby from home to car to stroller and back home. The ultimate in convenience, "Switch" the seat to face forward or backward, travel system compatible and easily closes to a compact "umbrella fold". The Pliko Switch Compact is newly designed to improve on the chassis by 2 inches of a shorter fold and 2 pounds lighter. It closes easily without the seat or with the seat attached in either stroller or carriage mode. The detachable cup holder and telescoping handles are two more features you will love.