Inner mold for ZH Racing rear tires, commonly used in Hang-On Racers. This is the "C (Expert)" type. Made with a 3D printer. The product in the first photo is what you will receive. (The exploded view in the third photo uses the B type (red).) Measured for ZH rear tires, it's slightly larger than the tire's inner diameter. Compared to B, it has a higher center profile, making it easier to lean into turns. If you've "tried the B inner" and want a bit more performance, try this C. Note that due to the slightly larger outer circumference, some modification is required for the kit's original swing arm and part of the lower section of the optional oil damper. See photo 5. Weight is "18.0g for the inner only" and approximately "64g with tire and wheel." The dimensions of the wheel and inner are properly adjusted, so "tires can be set without gluing" - see photo 4. (Glue if you have concerns when using a high-power motor.) After a year of making and testing, changing the shape and testing again, I've created something that roughly meets the required conditions. I hope you'll give it a try. Shipping will be via "regular mail" (定形外郵便). Instant purchase is OK without questions. By the way, I am the aforementioned "Chevron Models." I create these with a 3D printer (0.1mm layer thickness for precision) and assemble and finish them by hand, so I can't produce many. Therefore, they cannot be distributed through wholesalers or retailers like our other products. (The price is set to exclude the markup for direct sales.) Please understand. Thank you. Type...Radio Control