RX ring gaskets, an evolution of R types, fit the same grooves as R but offer pressure-energized sealing. The gasket's pressure-passage hole (in certain sizes) equalizes pressure across faces, enhancing reliability at higher pressures. RX gaskets do not allow face-to-face flange contact, relying on interference fit. Primary sealing occurs on the outer diameter where radial and axial l... https://globalsealstech.com/product-category/oil-gas-seals/api-6a-wellhead-equipment-seals/