The travel system kit allows you to attach your babys car seat directly on your pushchair from the car to avoid waking them up the kit is easy to attach to the frame of your pushchair and 2 kits can be attached for twins features easy to attach to the frame of your duo or duet pushchair one or 2 travel system kits can be attached compatible with the following car seats maxi cosi cabriofix maxi cosi pebble mountain buggy protect philteds alpha and cybex aton not included pushcha