The advent of more and more deepwater discoveries brings with them significant challenges. Deeper waters mean higher pressures from not only the wells, but also from the subsea environment. A well at 1,500 meters causes an environmental pressure on the valve of 150 bar or 2,175 psi. At these depths, it is necessary not only to keep the process stream in, but also to keep the environment out. Since in addition it is necessary to ensure the equipment meets a design life of over 25 years, the technology used on the pressure boundaries and on dynamic stem sealing applications, must work first time, every time. the majority of subsea equipment is required to conform to API 6A / API 17D PR2. This type of test requires the valve to undergo 160 ambient gas cycles at the maximum operating differential pressure prior to 20 cycles each at the maximum and minimum operating temperatures also on gas