ETA movement grades
The Swiss company ETA (now part of the Swatch conglomerate) makes mechanical watch movements that are included into an astonishing number of watches. Many, many premium watch brands (e.g. Omega, Oris, Hamilton, Tudor, etc, etc) use ETA movements.
Turns out that ETA ships five grades of movements, with differing degrees of accuracy, finish and refinement. So when you read ‘ETA 2824’, you need to think ‘what grade of 2824?’