PARVEEN Spang Link / Mechanical Jars utilise the weight of the stems connected immediately above to deliver powerful jarring impacts, by manipulating the wireline upwards or downwards. They are composed of two sections linked together which are free to extend or collapse. The effect of the jarring impact depends on the weight of the stems used, the length of the stroke, tubing size and deviation, fluid viscosity, well pressure acting on the cross section area of wireline and the speed of the wireline movement.