Two-action Drill Accelerator Type SZJQ can be stored energy by hydraulic spring. It should be applied with Model QY? Hydraulic Drilling Jar jointly. The drill collar and Hydraulic Jar (below the Drill Accelerator ) can function an accelerated effect when jarring operates as for making the stuck point gain more jarring force.
ABB Switching Protection & Accessories 1SCA151253R1001 
