Cylinder head plug is installed in the hydraulic cylinder. The cylinder head presses the  positioning plate tightly in the F1300/1600 mud pump. In the F800/1000 mud pump, cylinder head presses the cylinder device, which is pushing the cylinder liner.Cylinder head plug consists of a handle and a plug body , which are welded together. The blank of plug body is 45 steel, which is quenched as per the standard of HB217-255.