This specific 3D model, "Gas mask helmet 3d model scifi Low-poly Low-poly 3D model 328", 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.
MAX (Autodesk 3ds Max, filesize: 365 KB), OBJ (OBJ, filesize: 215 KB), FBX (Autodesk FBX, filesize: 365 KB)