Including 2 pcs of 19 mm diameter all-aluminum rollers, mounting screws and spacers. – It is a special specification in which the popular all-aluminum roller with a diameter of 19 mm is given a black alumite and the characters of TAMIYA JAPAN CUP 2021 are blueprinted. – Also a point to demonstrate smooth rotation by embedding 520 ball bearing in the bearing part. – Can be installed on various Mini 4WD including Mini 4WD PRO.(Some bodies need to be processed)