Deformation Lockout Tool is made to permanently lock the TRSSV in open position. This tool is a combination mechanical & hydraulic tool. Applied tubing pressure will move the flow tube of TRSSSV downwards keeping the flapper fully open. When tubing pressure is increased further, the deforming dogs will penetrate into the TRSSSV flow tube, making it permanently deformed. This deformation of the flow tube will prevent it from traveling back into the closed position thus keeping the flapper locked in open position.