Combination ring joint gaskets are two distinct API ring joint gaskets combined. These are used to join flanges that have different-sized API ring grooves on each flange but the same bolt circle dimensions and number of bolt holes. In addition to this, the said products are ideal for applications that include high pressure and high temperature. These are produced in octagonal and oval shaped cross sections. Combination ring joint gaskets create a robust seal between two mating flanges when used with RTJ flanges. The materials used to make gaskets are typically softer than the metal used to make the flanges they are sealing.