This specific 3D model, "Wedding Ring 3D print model 138", is an asset made available by "Unknown author".
You can download this asset for free at "Unknown platform" by following the link.
Usage of this 3d asset is subject to the "Unknown license" agreement.
STL (Stereolithography, filesize: 643 KB), 3DM (Rhinoceros 3D, filesize: 856 KB)