These are my own 3D-printed parts. They are prototypes, so there may be imperfections in the shape or functionality. The item in the second photo is a dummy coupler that doesn't move, but it can be coupled like a GM knuckle coupler. However, the clearance is tight, so processing such as filing is required. The item in the third photo is a dummy coupler with a moving knuckle, but it cannot be coupled. A 0.4mm brass wire is required for the axis that moves the knuckle. The buyer is responsible for providing the brass wire. If you have any questions, please feel free to comment.