This drilling jar consists of two components, the ZSJ  type drilling up jar and ZXJ type drilling down jar. These  components can be operated together or exclusively. The  up jarring portion utilizes the hydraulic system, allowing  the jarring force to be easily adjusted by the tool elevation  load. The jarring force should not exceed the maximum  rated load of the tools. The downward jarring portion utilizes the mechanical friction mechanism. However, the  jarring force can only be pre-adjusted mechanically on  the drilling jar prior employing it in the downhole drilling  operation.