This specific 3D model, "Women Ring MTL 3dm STL OBJ FBX Details 3D print model 23", is an asset made available by "Unknown author".
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Usage of this 3d asset is subject to the "Unknown license" agreement.
STL (Stereolithography, filesize: 24.3 MB), OBJ (OBJ, filesize: 70.7 MB), 3DM (Rhinoceros 3D, filesize: 42.2 MB), FBX (Autodesk FBX, filesize: 11.3 MB)