Spartan shield 3D model (Polygon mesh 3D model) is available on CGTrader for $2. Original author: cpolox. Specs: 2675328 polys, 1337920 verts.
BLEND (Blender, filesize: 185 MB), FBX (Autodesk FBX, filesize: 67.8 MB), STL (Stereolithography, filesize: 128 MB)