~★Adapted to deep oil reservoir, hard stratum and severe earthiness, offsore oil and natural gas exploitation.   
★ Maximum and minimum service life more than 4000hours.   
★Phase transformation toughen technology has various advantages   
    Wear-resistance, Erosion-resistance   
    High-pressure-resistance, High- temperature-resistance   
    High strength and high hardness.   
★ Cost of shipment, Maintenance, labor and Storage in the drilling works reduced .   
★ Better toughness properties and longer service life.   
     Reduce piston wear and water consumption for lubrication.