A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage from or into the joined objects while under compression.Gaskets are normally made from a flat material, a sheet such as paper, rubber, silicone, metal, cork, felt, neoprene, nitrile rubber, fiberglass, polytetrafluoroethylene (otherwise known as PTFE or Teflon) or a plastic polymer (such as polychlorotrifluoroethylene).
Some seals and gaskets
1. o-ring
2. fiber washer
3. paper gasket
4. cylinder head gasket
Since there is no single tariff classification or location in the tariff for all gaskets, the classification of gaskets is quite difficult and it depends on a variety of factors, including the composition of a gasket and where it is used. You may refer to U.S. Customs and Border Protection (CBP) publication on GASKETS for a detailed coverage of gasket classification.