This specific 3D model, "Viking helmet 3D model 12", is an asset made available by "Unknown author".
Can be downloaded at "Unknown platform" by following the link.
The licensing terms for this digital asset are governed by "Unknown license".
STL (Stereolithography, filesize: 1.84 MB), OBJ (OBJ, filesize: 2.99 MB), FBX (Autodesk FBX, filesize: 963 KB), PNG (PNG, filesize: 2.02 MB), GLTF (glTF, filesize: 2.81 MB), 3DS (3D Studio, filesize: 806 KB), MAX (Autodesk 3ds Max, filesize: 1.52 MB), USDZ (USDZ, filesize: 610 KB)