Seal washers are used as sealing components in mechanical and equipment applications, as well as in pipelines where fluids are present. They are materials that provide sealing, used both internally and externally. Seal washers are made from metal or non-metallic sheet materials, which are cut, stamped, or trimmed into shape, and are used for sealing connections between pipes and for sealing connections between parts of machinery and equipment. They can be categorized into metallic and non-metallic seal washers. The metallic types include copper washers, stainless steel washers, iron washers, aluminum washers, etc. The non-metallic types include asbestos washers, non-asbestos washers, paper washers, rubber washers, and more.