Rubber Gaskets, on the other hand, are often custom-shaped to fit more irregular or complex surfaces such as flanges, engine parts, or machinery joints. Gaskets are designed to fill surface irregularities and create a more comprehensive seal over larger or non-flat areas. This design makes rubber gaskets generally more efficient at sealing under high pressure and in demanding environments because they compress and conform to uneven mating surfaces, preventing leaks where washers might not provide enough coverage or sealing force.