Gasket rings for oval closures consist of a defined blended fabric. High-quality aramid fibers in combination with preoxidized carbon fibers guarantees high tensile and shear strength. A chrome steel wire reinforcement provides additional strength. The fabric is coated on both sides with special natural rubber in a sophisticated process that fills the fabric structure and results in high cross-section density. They are then wound into “continuous” rings, pressed and vulcanized.