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The ETA 2892-A2 is based on the original ETA caliber 2892 automatic watch movement.
Accuracy of the ETA caliber 2892-A2 can range from as much as +/-20 seconds per day to just +/-5 seconds/day. The accuracy that your watch experiences depends on the grade that the watch manufacturer chose to power their watches.
Similar to other ETA movements, there are 3 grades of production quality.
Elaborated Grade – Adjusted to four positions / average accuracy of +/-5 sec/day to +/-20 sec/day.
Top Grade – Adjusted to five positions / average accuracy of +/-4 sec/day to +/-15 sec/day.
Chronometer (COSC) Grade – Adjusted to five positions / average accuracy of -4/+6 sec/day.
The key components which differ at the line of demarcation between Elaborated and Top are the pallet stones, balance wheel & hairspring, and the regulator mechanism. The degree of decoration on the movement’s parts also increases with the grade. –Source