Teflon-coated o-rings are made by using silicon or viton as seamless and uniform core material which is enclosed in Teflon FEP or PFA capsule. Compared with PTFE o-ring, it has excellent performance in compression set and cold flow. In addition, it has almost the same performance as the perfluoroelastomer o-ring and is less expensive. High-quality capsules and core materials comply with FDA (US Food and Drug Administration) regulations and can be safely used in food and pharmaceutical fields.