$9 PBR SRS02 Sight Low-poly 3D model by steffe-engdahl. Available on CGTrader with 1306 polys and 700 vertices. Check it out on CGHub.
OBJ (OBJ, filesize: 213 KB), MA (Autodesk Maya, filesize: 146 KB), DAE (Collada, filesize: 201 KB), FBX (Autodesk FBX, filesize: 60.8 KB)