$9 MMA Training Centre Low-poly 3D model by militarymodels99. Available on CGTrader. Check it out on CGHub.
STL (Stereolithography, filesize: 15.7 MB), OBJ (OBJ, filesize: 10.2 MB), FBX (Autodesk FBX, filesize: 8.65 MB), BLEND (Blender, filesize: 3.68 MB), GLTF (glTF, filesize: 1.4 MB)