AT921?PTFE gasket,is made by cutting PTFE stick, pipe and sheet into flat shape, v shape gasket or valve annulus.it has 100% PTFE structure. it can bear the most bitter chemical medium, and has good anti-creeping performance. AT922-Expanded PTFE gasket , is a replacement of asbestos. it is anti-creeping, anti-cold-flow, anti-low-temerature.it has no pollution. it is easy to install and replace. under small pre-stress force, it can bear great internal pressure even in a environment of changing pressure. it is the best suit the condition with rough and fragile flange and alternately-changing temperature.