$2 M4 castle nut 3D model by VSJP1000. Available on CGTrader with 6000 polys and 3000 vertices. Geometry: Polygon mesh. Check it out on CGHub.
STL (Stereolithography, filesize: 341 KB), OBJ (OBJ, filesize: 546 KB), 3MF (3D Manufacturing File, filesize: 91.2 KB), OTHER (Other, filesize: 1000 KB), STP (STEP, filesize: 1.06 MB), DAE (Collada, filesize: 533 KB), IGE (IGES, filesize: 1.1 MB)