They're plastic rollers which may be employed for the rear roller setup. Dual rollers are suitable to setups for beginners specifically, because they are easy to fit, offer smooth, stable cornering, which help prevent your car from bouncing within the course wall surface thanks to the most truly effective rollers.
• Rollers are molded in low-friction POM plastic (black).
• Attachment of Item 94752 (520 ball bearings) and 94768 (Bearing Roller Spacer) provide more superior functionality.
• 13mm (top and bottom) Double Rollers x2
• Screws and steel components included.
• Compatible with the MA, VZ, and AR framework automobiles. Some systems may necessitate modification.