Military SCI-FI Helmet 3D model is available on CGTrader for $5. Original author: MekIra. Specs: 272920 polys, 276156 verts.
STL (Stereolithography, filesize: 10.9 MB), OBJ (OBJ, filesize: 10 MB), BLEND (Blender, filesize: 39.1 MB), FBX (Autodesk FBX, filesize: 15.2 MB)