Metallic Ring-Joints are produced according to the standard established by the American Petroleum Institute, API 6A and API 17D and the American Society of Mechanical Engineers, ASME B16.20, for applications at elevated temperatures and/or pressures. A typical application of Ring-Joints is the “Christmas Tree” used in oil fileds. The seal is obtained in a line of contact by a wedge action with high seating pressures, thus forcing the gasket material to flow. The small sealing area with high contact pressure results in great reliability. However the contact surfaces of the gasket and the flange should be carefully finished. Some styles of Ring-Joints are pressure activated, that is, the greater the pressure the better the sealability.