Features and performance one, extends the piston stroke, reciprocating smooth, for digging machines to minimize rebound; Second, optimize performance (piston), continuous performance improvement under emergency conditions using high quality special alloy steel; three ; HW Gao solder outstanding practicality and reliability; special alloy steel using high quality; four, nitrogen room safe start, saving energy; five, running lubrication, reducing wear and maintenance on time, keep working efficiency; six, piston and valve by precision heat treatment, to avoid scratches; seven, long lock lever, high strength spiral design, to avoid loss; eight, accumulators, hydraulic oil furnace to reduce irregular pulse pressure, supplementary accumulator pressure, improve combat force