| Brand | Oris |
| Caliber Number | 644 |
| In-House? | No |
| Base Caliber | ETA 2836-2 |
| Movement Type | Automatic, self-winding mechanical |
| Lignes | 11.5”’ |
| Diameter | 26mm |
| Casing Diameter | 25.6mm |
| Height | 5.05mm (unconfirmed) |
| Jewel Count | 27 |
| Beat Rate | 28,800 vph, 4Hz |
| Lift Angle | 50 degrees |
| Power Reserve | ~38 hours |
| Rotor Style | Ball-bearing |
| Rotor Winding Direction | Bi-directional |
| Hand-Windable? | Yes |
| Anti-Shock Device | Incabloc |
| Balance | Glucydur |
| Hand Count | 4 |
| Functions | Central hours; central minutes; small seconds at 9:00; central pointer date hand |
| Hacking Seconds? | Yes |
| Country of Manufacture | Switzerland, Swiss made |
| Known Models | Oris Classic Pointer Date (Add your watch to the comments below…) |
The Oris caliber 644 is an automatic watch movement with a small seconds subdial at 9:00 and a pointer date hand. This caliber is based on the ETA 2836-2 and was introduced as far back as 1997.
The 644 has the characteristic red rotor that Oris is known for.
Oris 644 VS 641:
There is a similar caliber 641 with the main difference being that the 641 is the certified chronometer (COSC) version of the 644.
644 VS 645:
Oris calibre 645 watches look like 644 powered watches from a distance, but upon closer inspection, the central pointer hand on the 645 is a pointer day, compared to the 644’s pointer date. The 645 has a datewheel with a date window at 3:00.
Additional Resources:
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Thank you for sharing.
This movement in gold tone can be found in the Marloe Coniston