DESCRIPTION These are tapered versions of the smooth-spinning ball bearing rollers from Item 15464 JR HG Alum Ball-Race Rollers 19mm (Ringless). Tapering them encourages the car to stay on the course when it mounts the walls, with the aim of raising your race completion rate! • Tapered Aluminum Ball-Race Rollers x2 • Purple anodized finish. • Built-in 520 ball bearings. • Screws and spacers for use in attachment included. • Compatible with Mini 4WD PRO and Mini 4WD cars. Some bodies may require modification.