Corrugated metal gasket is the concentric waveform ring processed from a flat metal ring through molding, rolling or turning, with the nonmetals like the expanded graphite or PTFE pasted on the surface. Compared to the serrated gasket, its inside linings are of a variety of thickness, such as 3mm, 2mm, 1mm, 0.5mm, etc., and the pitch of waves differs in accordance with the width of metal sealing surface, generally being 3mm, 4mm, and 6mm. Metal serrated gasket，is processed into concentric grooves on both sides of stainless steel flat gasket by use of precision lathes. Flexible graphite, PTFE, non-asbestos sheets or other soft metals can be pasted on its two sides according to different mediums. It can be also directly used without sealing layer, and achieves a good sealing effect. But it will easily damage the surface of the flange under a high pressure. Metal ring gaskets，are the sealing gaskets of various forms processed from the solid metals of various materials through mechanical cutting by high precision CNC lathes. Featuring small installation area and high pretension pressure, they are applied in sealing parts of pressure vessels, valves and cylinders in the environments of high temperature, high pressure and high corrosiveness.