Monta · Switzerland
Monta M-23
The M-23 is Monta's GMT-capable caliber, introduced to power the brand's dual-timezone models — most visibly the Skyquest GMT (circa 2023) and the Noble Voyager (2024). Earlier documentation places the designation on a Sellita SW330-1 or ETA 2893-2 base with a 42-hour power reserve; current production rests on the Sellita SW330-2, which Sellita announced in July 2020 and which extended the typical power reserve to 56 hours.
The SW330 family shares the lineage and similar dimensions of the ETA 2893-2, the industry's thin-GMT workhorse used for decades across the Swiss industry. The M-23 sits squarely in that lineage. The GMT implementation is the 'caller' (independent hand) style — the 24-hour hand quicksets separately from the main hour hand.
Monta recommends returning watches to its own service center; genuine MONTA parts are only available through that service center, and unauthorized third-party work voids the warranty. The movement is not widely licensed beyond Monta's own lineup, making it effectively an exclusive branded variant rather than a broadly distributed caliber.
Hz
Jewels
Reserve
In catalog
Technical specification
| Manufacturer | Monta |
| Origin | Switzerland |
| Type | Automatic |
| Beat rate | 28,800 bph · 4 Hz |
| Jewels | 25 |
| Power reserve | 56 h |
| Diameter | 25.6 mm |
| Height | 4.1 mm |
| Hacking seconds | Yes |
| Hand-winding | Yes |
| Date | Yes |
| GMT | Yes |
| Chronograph | No |
| Based on | Sellita SW330-2 |
1 model
Watches with this caliber
FAQ
Is the Monta M-23 automatic or manual?
The Monta M-23 is an automatic (self-winding) movement: a rotor winds the mainspring from the motion of your wrist, so it needs no battery. It can also be wound by hand via the crown.
What is the power reserve of the Monta M-23?
About 56 hours on a full wind — into a second day, so it keeps running overnight off the wrist. Power reserve is how long the Monta M-23 keeps running once you stop wearing or winding it.
Does the Monta M-23 hack (stop the seconds when you set it)?
Yes. Pulling the crown stops the seconds hand, so the Monta M-23 can be set precisely to a reference time before you push the crown back in. Hacking is what lets you sync several watches — or a watch and a phone — to the exact second.
Does the Monta M-23 have a date function?
Yes — the Monta M-23 can drive a date display, though whether a given watch actually shows the date depends on the dial the maker chose, so check the individual model rather than the movement.
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