These are repair parts born from consultations! Do you have any vehicles where the part that attaches the coupler has broken? These are the parts to replace that. We've received messages from those who purchased these, saying they were able to successfully repair their vehicles at home! Why not revive the coupler on your vehicle that you'd given up on? The black parts in the last photo are the product! We've designed two types of repair parts shown in the photos, so they are compatible. We'll give you both types, so you can try them out with confidence ٩(ˊᗜˋ*)و We offer a set of A and B for 450 yen! Type A Can be used for chassis of commuter trains, limited express trains, etc. The following are the compatible dimensions: ・Boss diameter in the photo is approximately φ8mm ・Inner dimension of the chassis is approximately 13mm Type B Shinkansen (bullet trains) and some leading cars The following are the compatible dimensions: ・Boss diameter in the photo is approximately φ8mm ・Inner dimension of the chassis is approximately 14.5mm Basically, Type A can be used with modification even if the above dimensions don't match. Please consult with us. Type B is actually running in my home. You will need to cut some of the ribs inside the car body, so please refer to the photos m(_ _)m You can easily cut them with a carving knife (flat blade) or similar tool. Some vehicles may require modification. Recommended only for those who are good at carving and modifying things themselves ☺︎ For bulk purchases, the second item and beyond will be an additional 100 yen. Feel free to comment, and we'll be happy to answer your questions ^_^