Sellita Cal. SW330-1 and SW330-2 is a thin automatic GMT movement. It is based on Cal. SW300-1, a clone of ETA’s 2892A2. SW330-1 and SW330-2 is thus very similar to the ETA Cal. 2893-2.
Sellita SW330 History
Sellita had long produced movements for ETA, and re-sold assembled kits of Cal. 2892-2 and 2893-2 as late as 2008 with ETA branding. The company also specialized in custom finishing of these movements for many Swiss watchmakers. In 2008, Sellita switched to their own-brand SW300 movement family, though most of the components remained identical. The assortment was still sourced from Swatch Group’s Nivarox but the remaining components were transitioned to other suppliers.
Like the SW200 family, Cal. SW300 was updated shortly after introduction with new more durable tooth profiles as well as updated bridges for the reverser wheels. Movements with this update are denoted with the “-1” model number, and non “dash-1” movements are rarely seen. By 2013, Sellita developed a new pallet bridge for the SW300 movements, eliminating a screw and threading of a positioning hole. These components are interchangeable and do not change the movement name.
In 2015, Sellita introduced a clone of ETA’s GMT movement, Cal. 2893-2 called SW330-1. This was updated in March 2020 with six new components to become Cal. SW330-2. In 2021, a new barrel and mainspring increased power reserve from 42 to 56 hours.
Many complain that Cal. SW330 (and ETA’s 2893-2) is not a “true GMT” because the quick adjustment in position 2 advances the 24 hour hand rather than the 12 hour hand. Thus, the “home” or running time is displayed on the 12 hour scale while the “away” time is shown on the 24 hour scale. GMT movements in the Rolex GMT-Master II and similar models from Omega and others have an adjustable 12-hour hand, so the 24 hour hand always displays “home time.”
Sellita SW330-1 Applications
Cal. SW330-1 is used as a replacement for ETA’s 2893-2, often without a mention of the supplier change.
- Mühle Glashütte Mühle SW 330-1 (with a woodpecker regulator)
- Oris 798
- Ming 17.09
Sellita SW330-2
In March 2020, Sellita issued a tech note detailing the release of an updated version of Cal. SW330. The new movement, designated SW330-2, features six updated components in the GMT wheel train “to improve the functioning and the quick setting of the GMT function.” In practice, it appears that these components reduce the “slack” or “play” in the GMT hand setting but do not fundamentally alter the function of the watch. These changes caused some issues for Ming’s 17.09, requiring some redesign to their modified SW330 movement.
The modified components are the GMT wheel, hour wheel, intermediate date wheel, intermediate corrector setting wheel, corrector setting wheel, and double corrector. These six components must be used together and can be retrofitted to Cal. SW330-1 to update its functionality. Old movement plates fitted with the new wheel set are marked “SW330-1” with a “+” inscribed, but new movement plates read “SW330-2”.
Sellita SW330-2 Applications
Cal. SW330-2 is appearing in many watches starting in 2021:
- Christopher Ward C63 Seelander GMT
- Ming 22.01 GMT
Sellita SW300 Family
The SW300 family consists of just three movement models with three simple complications: Date wheel, 24 hour hand, and small seconds. These movements are widely used, however, especially Cal. SW300-1, now that ETA has restricted sales of the similar Cal. 2892A2.
Note that Sellita SW300 movements have four more jewels than their ETA 2892-based counterparts. In 2021, Sellita began fitting all SW300 family movements with a new barrel with longer power reserve of 56 hours rather than the 42 previously specified.
| Calibre | ETA Equivalent | Jewels | Complications |
|---|---|---|---|
| SW300 SW300-1 | ETA 2892A2 | 25 | Date |
| SW330-1 SW330-2 | ETA 2893-2 | 25 | Date and 24 Hour Hand |
| SW360-1 | ETA 2895-2 | 31 | Date and Small Seconds |