Uses holes for 9mm, 13mm, and 19mm rollers.
For added rigidity, ABS resin with fiber-glass is used.
One slide return spring is included.
When equipped with the standard 13.8mm rubber roller, the cars width becomes 105mm.
Two newly designed mushroom shaped rollers are included.
Assembly of the roller stay on the bumper is possible.
Can be used with the each following Mini 4WD Pro Cars; VS, Super X, Super TZ-X,Super TZ, and Super FM chassis.