| Manufacturer | Cartier |
| Caliber Number | 045 MC |
| Dimensions | 25.60mm diameter, 3.80mm thick |
| Vibrations Per Hour | 21,600 bph, 3 Hz |
| Power Reserve | 40 hours (chrono off), 34 hours (chrono on) |
| Jewels | 22 |
| Functions | Hours, minutes, small seconds, 30 minute counter, chronograph |
| Country of Manufacture | Switzerland |
| Known Models | Tortue Mono Poussoir |
In an excellent article by GEO at Revolution Magazine he says the following:
The calibre 045MC also has the special feature of a clutch system with a swivel pin. Which in fact means, that the transmission of the movement of the second wheel of the base movement to the chronograph’s central wheel, is effected through a double swivel pin. The advantage of this clutch, is that it suppresses the skip of he hand at the beginning of a translation movement, which is found with the mechanisms of chronographs with a lateral clutch.
This handwound movement is a THA ebauche. THA is a company that was formed by ‘Halter, Journe & Flageollet’, so this calibre is their work. To my knowledge the caliber 045MC was only used for the various Cartier Tortue Mono Poussoir models, the Tank Mono Poussoir and the Debethune Mono Poussoir.
SJX mentions the clutch system in this post:
Note the emphasis on the clutch system of the cal. 045MC, which eliminates the annoying seconds hand jump found in many chronographs.