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ISO 3764:2016
Timekeeping instruments - Movements - Types, dimensions and nomenclature
ISO 3764:2016 specifies the types and fitting dimensions of mechanical and electromechanical watch-movements.
This International Standard is applicable to the five following types of movements:
- Type 1: round;
- Type 2: shaped round;
- Type 3: round with double cutting;
- Type 4: 5 ½′′′;
- Type 5: 6 × 8′′′.
International Organization for Standardization [iso]