Model “DX” Jar belongs to the advanced product of   Surface Bumper Jar Type DJ . It can adopt lock mechanism with higher reliability. And   the jarring operation can be performed for many times and long service. Also, down-jarring can be operated continuously. The jarring force can be adjusted conveniently on drill platform. It can not only bear heavy load and strong torque but also have good sealing property and withstand the slurry circulation of high pressure produced by the pump.