Note: the labels in parenthesis are what ETA calls their similar grades. Some watch brands describe their Sellita movements with those terms because “Elabore” and “Top” are more recognizable by watch collectors who are familiar with ETA movements.
How to tell the difference between grades?
One way to distinguish between Standard/Special and Premium/COSC grades of Sellita is to look at the anti-shock device:
The pallets on the Standard/Special grade are polyrubies. On Premium and COSC grades the pallets are red rubies.
Similarities Between Grades:
Despite differences in accuracy and some parts, all grades share some common features:
The escape wheel is polished, epilame-coated, and uses molybdenum disulfide (MoS2).
The pallet forks are polished.
The balance wheel is gilt.
The hairspring collet is Nivatronic.
The balance staff is epilame-coated.
In addition to the different grades, there are also different finishes: Standard, Refined, and Tailor Made. The images below are a side-by-side comparison between the Standard and Refined finishes.
It is important to note that the information above is based on the standard offerings from Sellita. Watch brands may opt to make their own modifications depending on their own standards. For example, this Maurice Lacroix caliber ML115 is based on a Sellita SW200-1, and is said to be a Special (Elabore) grade, however, it has an Incabloc anti-shock device instead of Novodiac. It is unknown whether the movements came this way from Sellita as a special order, or if Maurice Lacroix made the modification themselves. Just keep in mind that the grading system is a base, but don’t be surprised if you see differences. It would be nice if watch companies were more transparent about the ebauches they use and what changes they make to them. Please comment below if you know of other calibers like this.
Sometimes the difference between grades seems like a difference between movements. Many of us buy a watch knowing it is powered by an SW200-1, but no idea as to the grade, therefore not knowing how many positions it was tested in or what to expect as far as accuracy. It would be nice if brands were more transparent about the grades they use, or if manufacturers like Sellita would develop a way to identify the grade of their movements from a design element or new caliber designator… but such is the smoke and mirrors of the Swiss watch industry.