No. Car seats differ. Isofix is a strong metal fitting in a car that allows a base to be fitted without using the normal seat belt buckles. At the base of the rear seats is a strip than can be moved to reveal two metal loops that the base can clip onto. Some cars do not have Isofix fittings so check your car before considering an Isofix. Car seats that don’t fit to Isofix points are held on via the seatbelts.