PEEK (polyetheretherketone) backup rings in API 6A seals provide superior anti-extrusion support at elevated temperatures. Unfilled or carbon-filled grades resist creep and maintain shape up to 500°F, preventing elastomer blowout in high-pressure annular and valve applications during extended service life. https://globalsealstech.com/product-category/oil-gas-seals/api-6a-wellhead-equipment-seals/