Introduction The Don-Nan On-Off Tool provides an operator with the means of either connecting or disconnecting from a sucker rod string, at any point, based on the location of the tool in the rod string. The On-Off Tool is attached directly to the sucker rod string, at the point that the operator prefers to make the disconnection. The tool is connected by setting down weight in the bottom latch section and rotating the rod string in the opposite direction. It is disconnected by turning the rod string and picking it up. It may also be used as a safety joint. Advantages & Applications Virtually eliminates the added costs of stripping jobs, increased rig time due to failures and damaged equipment. Provides a means of running oversized tubing pumps permitting additional plunger displacement without replacing the entire string. In crooked holes, metal plungers for tubing pumps may be run in the well in the barrel assembly, eliminating the possibility of damaging the plunger while lowering it through the tubing on the sucker rod string. May be used in sandy wells, where it is difficult to pull the pump assembly.