Phelps expanded PTFE sheet is made from 100% expanded PTFE. A soft gasket material designed for high performance service in extreme caustic to acid chemicals. This material has all the benefits of Virgin PTFE sheet, but with significantly less creep and cold flow that is commonly associated with Virgin PTFE. It conforms to rough sealing surfaces, yet compresses into an extremely tough gasket that makes a tight, long lasting seal. Expanding Virgin PTFE inherently has no structural weakness because it has a uniform and highly fibrillated microstructure with equal tensile strength in all directions.