... Hydraulic Breakers,Front Cylinder,Rear Cylinder,Middle Cylinder,Piston,Main Valve and so on. Technology:1.Raw Material: 20 Crmo2.Equipment ... factory7.Cylinder: CMM Inspector,Axiality controll within 0.003mm8.Main Valve: Heatment ,the gap controll within 0.025mm9.Piston: Strict Grinding ...