This is a small tank tracks. I hope to upload more similar robots soon; I have the intention of making a robot based chess set once I have made enough of them.If you are using the stl file, I suggest you scale the model up by a factor of 1.6 in Cura. This will increase the size from 15mm x 15mm to 24mm x 24mm, which if slightly larger and shows the details slightly better. I would have made this addition in openSCAD but it was playing up!