$15 piston design 3D model by bubercreative. Available on CGTrader. Check it out on CGHub.
SLDPRT (SolidWorks, filesize: 213 KB), DWG (AutoCAD, filesize: 213 KB), FBX (Autodesk FBX, filesize: 213 KB), DXF (DXF, filesize: 213 KB), BLEND (Blender, filesize: 213 KB), STP (STEP, filesize: 213 KB)