These are new, 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 (Ringless) x2 - Built-in 520 ball bearings give smooth rotation. - Screws and spacers for use in attachment are included.
