Abstract: A valve suitable for use with high pressure fluids comprises a valve housing formed as an integral body, a valve cap which is releasably secured to the valve housing, and an operating gas manifold body secured to the valve housing body. The operating gas lines can be secured to the manifold body by screw fittings and sealed to conically contoured passageways in the valve housing by correspondingly conically contoured ferrules. An end closure for the valve housing is held in place against spring bias by a split retention ring to provide a chamber for gas assist to an operating piston in high pressure applications.