TISSOT cal: 28.1 - 31.21
The first Automatic movement from Tissot was introduced in 1943 with the cal: 28* and the 28.1 which was abondoned already in 1944 as the cal: 28.5.1 and the similar 31.1 with larger plate was introduced.
*Note, we have no official documetation at all covering the cal: 28, just the pictured movement.
Versions:
- 28: 1943? sub second
- 28.1: 1943 - 1944, sub second.
- 28.21: 1943 - 1944, sweep second.
- 28.5.1: 1944 - 1953, sub second, plate with mounting flange.
- 28.5.21: 1944 - 1953, sweep second, plate with mounting flange.
- 28.5N.21: 1951 - 1960, sweep second, second time zone, Navigator.
- 31.1: 1944 - 1953, sub second, bigger plate.
- 31.21: 1944 - 1953, sweep second, bigger plate.
