Gasket
A gasket is a rubber ring fitted at the crown, caseback and crystal that keeps water and dust out. It compresses as the watch closes, sealing the gaps. Because rubber hardens and loses its spring with age, gaskets need periodic replacement.
At a glance
- Material
- Rubber or synthetic elastomer (O-ring)
- Critical locations
- Crown, caseback, crystal
- Maintenance
- Inspected at each service or battery change
Keeping a watch sealed against water and dust does not rely on one part, but on several small rubber rings spread through the case. They fill the gaps as they compress, yet rubber is not a permanent material.
Where the gaskets sit
A typical watch has three critical points:
- Crown: opened and closed for winding and setting, so this gasket wears the fastest
- Caseback: the wide ring that closes off the movement
- Crystal: the seal that protects the dial and movement from above
Screw-down casebacks and a screw-down crown spread the pressure evenly, which makes the seal more reliable, so sound gaskets at those points are central to a watch holding its water resistance rating.
Why they get replaced
Rubber hardens, cracks and loses its spring under heat, perspiration, lotions and time. A stiff gasket can no longer fill the gap, and moisture seeps in. On a water-resistant watch the gaskets are inspected at every service or battery change, then the seal is confirmed with a pressure test. For habits that keep a watch sealed, read our guide to the best dive watches under £500.
Examples
On a dive watch with a screw-down crown and screw-in caseback such as the Orient Mako 3, the gaskets are the heart of the seal: the ring fills the gap and keeps water out once the crown is screwed firmly home.
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Comparison
A fresh gasket and a worn one behave very differently.
| Option A | Option B | Notes |
|---|---|---|
| Fresh gasket | Worn gasket | A fresh gasket stays supple and fills the gap when compressed; a worn one hardens and cracks, letting moisture seep through. |
Related terms
Watches that show this
Frequently asked questions
How often should watch gaskets be replaced?
Common practice is to inspect the gaskets at every full service and every battery change, replacing them when needed. On a water-resistant or regularly worn watch, that usually means replacing them every few years, after which a pressure test confirms the seal.
What does a worn gasket do to a watch?
A hardened or cracked gasket can no longer fill the gap, so moisture and dust can get in. The first sign is often fogging on the inside of the crystal, which should be taken seriously because it can lead to rust in the movement.
Does a watch need retesting after a gasket change?
Yes. After new gaskets are fitted, a pressure test confirms the case actually seals. The test measures resistance without wetting the watch and catches a gasket that was seated wrong or damaged before the watch ever gets wet.