Pressure plug

A pressure plug for shutting off pressure in a fluid transmission line as not to interrupt the flow through the main line, comprising of a main cylindrical outer tube externally threaded its full length having one end shaped to fit a wrench, the outer end flared outward, said wrench fitting having a maximum outside diameter less than the outside diameter of the main tube, an inner cylindrical rod, externally threaded at one end, to fit one or more locking and tightening nuts, said rod having a length greater than the outer tube and an outside diameter less than the inner diameter of the outer tube, a flared tubing nut main guide internally threaded at one end to fit the outer tube and internally threaded at the other end to receive a service valve fitting, said flared tubing nut main guide configured or grooved internally to accept a sealing ring, attached to the end of the inner rod opposite to the locking and tightening nuts an elastomer plug assembly capable of being expanded externally by compression, said elastomer plug assembly utilizing pressure in transmission pipeline sealing aperture in pipeline, said elastomer plug assembly consisting of a tube of elastomer material disposed between retainers on the end of the inner rod and an elastomer seal and retainers at the point of contact with the outer tube and elastomer plug assembly.