Monta Caliber M-23 Watch Movement

Manufacturer	Monta
Caliber Number	M-23
In-House?	No
Base Caliber	ETA 2893-2 or Sellita SW330-1
Movement Type	Automatic, self-winding mechanical
Lignes	11.5”’
Diameter	26.20mm
Casing Diameter	25.60mm
Thickness	4.10mm
Jewels	21 or 25 (depends on the case caliber)
Beat Rate / Frequency	28,800 bph / 4Hz
Lift Angle	51 degrees
Power Reserve	42 hours
Anti-Shock Device	Incabloc
Functions	Central hours; central minutes; central seconds; central GMT hand; date at 6:00
GMT Style	Caller GMT
Hacking Seconds?	Yes
Quick Date?	Yes
Country of Manufacture	Switzerland, Swiss made
Known Models	Monta Atlas, Monta Skyquest, Monta Noble Voyager

The Monta caliber M-23 is an automatic movement used in the microbrand’s Atlas and Skyquest models. It features a second time zone via a centrally located GMT hand, as well as a date window located at 6:00.

In Monta’s own words:

“The MONTA M-23 caliber is an automatic movement featuring a beat rate of 28,800 beats per hour (4 HZ) and displays hours, minutes, seconds, date, and GMT functions. It also features hacking seconds to allow for precise synchronization. Manufactured and assembled entirely in Switzerland, it is designed for an active lifestyle and features a 42-hour power reserve.” -Monta

Base Movement:

This movement can be based on either an ETA caliber 2893-2 or Sellita SW330-1, making it what Caliber Corner calls a Forrest Gump movement.

In this post on Instagram, @montawatch says:

“The Skyquest features our MONTA caliber M-23 which is either a Sellita SW330 or ETA 2893-2 base movement. We add a custom rotor and our in-house watchmaker performs the final QC to ensure accuracy.”

There doesn’t seem to be an option to select one or the other when placing an order on their site. If you have a Monta timepiece with this movement, please comment below which base movement you received and share your experience with selection.