Use a precision cold drawn seamless steel tube, strong honing process; bore sizes from φ40-φ400, length up to 3 meters, rod selection 40Cr, and then quenched to the surface of the first high-frequency hardening, the outer surface of hard chromium plating process to within the tough outer hard surface finish, rod diameter φ5-φ140, production, assembly workmanship and high quality NOK seals, fuel tanks are manufactured through high pressure test bench testing, a reliable quality assurance.