Water resistance is one of the easiest watch specifications to misunderstand. A 10 ATM label sounds like permission to dive to 10 atmospheres, but the number is a test classification for a complete watch, not a working depth printed on the dial. Real exposure involves movement, pressure changes, the crown, gaskets and the condition of the watch.
For a B2B brief, the useful question is not simply “3, 5 or 10 ATM?” It is what the customer expects the wearer to do, which parts can affect the seal, and whether the marking survives everyday use as well as the first laboratory check.
What 3, 5 and 10 ATM mean at the wrist
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These ratings describe increasingly demanding water exposure. The exact claim must still follow the standard and test method named in the market where the watch will be sold.
| Marking | Nominal static-pressure equivalent | Typical buying brief | What still needs checking |
|---|---|---|---|
| 3 ATM | 30 m | Rain, splashes and brief hand washing. | Crown position, caseback seal and whether the wearer might swim. |
| 5 ATM | 50 m | Everyday wet conditions and light water exposure. | Gasket fit, crystal seating and any claim about swimming. |
| 10 ATM | 100 m | Stronger water exposure for a sports-oriented model. | Crown tube, pushers, caseback threads and testing of the assembled watch. |
The meter values are nominal static-pressure equivalents, not recommended swimming or diving depths. A watch rated 10 ATM can still fail if the crown is left out, a gasket is pinched, or a pusher is operated underwater.
Water resistance is a system, not a gasket
The case is only one part of the barrier. Water reaches the movement through a chain of interfaces:
- Caseback — a screw thread or press-fit joint must seat evenly and compress its gasket without twisting it.
- Crown — the tube, stem seal and crown position determine how the opening behaves when the crown is pushed or pulled.
- Pushers — chronograph pushers add seals and openings that need their own review.
- Crystal — the crystal must sit squarely against its sealing surface; a distorted gasket can create a path even when the parts appear tight.
- Case finishing — sharp edges, damaged threads or excessive polishing can interfere with sealing surfaces.
We make our own watch cases, while movements and straps are sourced to match each model and market. That makes case and seal geometry controllable during development, but it does not remove the need to test the finished assembly. A gasket supplier’s specification and a case drawing are inputs, not a water-resistance result.
How to write a useful water-resistance brief
Before discussing a sample, put these points into the specification:
- Target marking — 3, 5 or 10 ATM, with the relevant market standard.
- Intended exposure — rain, hand washing, sports, swimming or only occasional splashes.
- Case construction — caseback type, crown style, pushers and crystal material.
- Operating conditions — whether the wearer may press pushers with wet hands or use the crown near water.
- Inspection requirement — the test method, pass/fail record and responsibility for the final declaration.
This prevents the sample room from chasing a rating the product does not need and gives the production team a clear acceptance rule. For reference constructions, compare complete watches in the watch catalogue; for the development route, see our OEM/ODM services.
What we examine before approving a sample
We begin with the dry assembly. The caseback is opened and closed repeatedly, thread engagement is checked, the gasket is examined for pinching or dry spots, and the crown is operated through its normal positions. On a chronograph, each pusher is checked for free return and seal seating.
Only after those checks is the complete watch treated as the test object. Testing a bare case makes it too easy to miss a leaking crown tube, a crooked crystal gasket or a pusher that does not return fully. The customer’s target rating, crown position, test duration and recording method should be agreed before production, with any deviation recorded rather than explained later.
Water resistance must also remain realistic in the sales description. Use the marking, the tested condition and the market standard consistently; do not translate 10 ATM into a promise that every wearer can dive to 100 m. The FAQ can explain service and warranty questions, while the services page covers development from a brief to an approved construction.
Full customization starts at 300 pcs per model; changing only the dial logo on an existing reference starts at 200 pcs. Samples usually take 15–20 days, followed by 30–45 days for production after approval. Send the intended water exposure, case construction and target market early, because those decisions shape the seals, crown and testing plan before the sample is built.
