This is an arm I designed for a giant humanoid robot. You can plug in a hand but also tools, guns or else.
OBJ (OBJ, filesize: 55.2 MB), 3DM (Rhinoceros 3D, filesize: 28.5 MB), FBX (Autodesk FBX, filesize: 13.6 MB), STP (STEP, filesize: 27.3 MB), IGE (IGES, filesize: 27.8 MB)