Just like some ETA movements, Sellita calibers are also available in different grades: Standard, Special, Premium, Chronometer.
These ratings may vary between specific caliber numbers, but here are the specs for the popular SW200-1 and SW215-1 which many Sellita movements are based on.
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.
Despite differences in accuracy and some parts, all grades share some common features.
In addition to 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.