PARVEEN Self-Releasing Overshot are used to fish wireline tools that have no fishing neck as well as damaged wireline tools and sucker rods that cannot be fished with a magnet.The tool is operated by applying the weight of the tool string on to the fish, which engages the fish. The harder the operator pulls on the overshot, the tighter the grip of the slips on the tool to be fished becomes. Should it proves impossible to free the jammed tool, a safety device permits the overshot to be released by jarring down. Once the overshot has been recovered, it is possible to change the size of the line to obtain a stronger jarring effect.