A new all-metallic seal has been tested and produced by The B.F. Goodrich Co. This seal, which is adapted for rod or piston service, dynamic or static applications, has been operated successfully at temperatures from -65 to 560 F. The temperature range was limited only by the fluids used. The pressure test range extends to 35,000 psi, which is not a design limit. Break-out force can be adjusted with very low or no leakage of the fluids or gases. The concept is that of a blunt knife edge that forms the radial or axial edge of a flexible diaphragm.