These materials include PTFE, PTFE-Gortex, Aflas, Neoprene, Nitrile-D, Urethane, Cord stock is O-Ring material, ready to be cut to create custom size O-Rings. There is a large selection of cross-sections available, and can be cut to any length you need. If this is a static application, this is a great solution. If the O-Ring will be moving, spliced and vulcanized O-Rings are much sturdier. Standard or Imperial sizes come in fractions of an inch. Cord Stock is sold by the foot.