Wristwatch · La Chaux-de-Fonds
Wristwatch with apertures
VerifiedThe rectangular case has a slightly curved back to hug the shape of the wrist. The black varnished upper part has three apertures displaying the hours, minutes and seconds on rotating disks.
Technical facts
- Inventory number
- MIH I-870
- Object type
- Wristwatch
- Place of production
- La Chaux-de-Fonds
- Dating
- 1940
- Materials and techniques (catalogue wording)
- Nickel chromé, vernis, laiton
- Dimensions (catalogue)
- dimensions min/max: 36 x 40 mm; poids: 26.000 g
- Inscriptions (catalogue)
- NICKEL CHROME 96 (Boîtier); PATENT FHF RALCO 15 JEWELS (Mouvement)
Historical significance
- The rectangular case has a slightly curved back to hug the shape of the wrist. The black varnished upper part has three apertures displaying the hours, minutes and seconds on rotating disks.
- The fifteen-jewel tonneau-shaped movement is fitted with a lever escapement and a monometallic balance with an self-compensating flat balance spring.
- Wristwatches with apertures appeared in 1931 at the Swiss Watch Fair and were still popular five years later.
Photographs

Photographs are illustrative examples of the type, not necessarily the exact object described. Verify details against the source file page.
Sources & references
- Musée international d'horlogerie, online collection record, inv. I-870: https://collection.mih.ch/fr/collection/item/38447/
Where sources disagree, the disagreement is stated rather than resolved silently.