How to Identify ETA Movement Caliber Numbers
James recently asked Caliber Corner:
I have an ETA movement I removed from a Royce military style however all I see is the ETA logo no caliber number. How do I find out what movement I have?
Below are some example of ETA movements with the caliber number location circled. If you have an ETA movement with the caliber number in a different location, please talk about it in the comments section.
The caliber number on automatic or mechanical ETA movements will almost always be stamped near the balance wheel. Sometimes it’s difficult to see unless you hold the watch at an angle. You may also need a loupe or macro camera lens as this caliber number can be quite small and difficult to read.
Vintage Mechanical Movements:
Although vintage watches with ETA produced movements may not be clearly stamped with the ETA logo, you can typically find the caliber number near or under the balance wheel similar to modern ETA movements.
The caliber number on quartz ETA movements can be found in several places depending on the movement. It will most commonly be a 6 digit number in the form of XXX.XXX. Try to locate this number either printed on the movement or stamped on the plate near the battery or coil. With some movements, you may have to remove the battery to get a clear view. Here are some examples…
What if you can’t find the number?
If you can’t find the number, or the caliber number has been worn off, you can play Sherlock Holmes and attempt to figure out the caliber by comparing the parts. Start with the bridge as the easiest way to begin your deductions.