Gasket
A sealing component used around case openings to help protect a watch against water, dust and contaminants.
Also known as: Seal, O-ring, Sealing gasket, Watch seal
Definition
A gasket is a compressible sealing component placed between mating watch parts to help prevent water, dust and other contaminants entering the case. Gaskets are commonly fitted around the caseback, crystal, crown, pushers and other openings. They are usually made from elastomeric materials and work by being compressed between surfaces to create a seal. Gaskets age, harden, deform and can be damaged during opening, so water resistance depends on their condition as well as case design and assembly.
Why it matters
A watch may look intact while its seals have deteriorated. Gasket condition is therefore one reason water resistance should be pressure-tested after servicing and periodically on watches regularly exposed to water.