Car simple. Ball bearing car in hard black anodized aluminum with four ball circuits: 2 Torlon ball circuits (lower) and 2 Delrin ball circuits (upper). The car will remain on the track even after ball bearing failure (overload). Side windows for easy maintenance and ball bearing cleaning and/or replacement. The car, the track and all components are extruded in high strength alloy and hard black anodized (steel parts: AISI 316). The sheet block is not included