I'd like to identify the manufacturer of these crystal units. Apparently the first line contains the frequency information (8 MHz, 16 MHz...).
The second line starts with a small 'e' which is probably a manufacturer signature.
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Sign up to join this communityEpson devices have an "e" on them, but almost all I've seen use a capital "E".
And ECS devices normally have the full "ECS".
The only match I can see is Abracon, who use e2 to denote temperature stability. See this datasheet for one of their units, where e2 means +/-20ppm over the range -20°C ~ +70°C. However that is far from a definite match.
@nanash1 found it !
The small "e" mark is used on Automotive qualified crystals of Seiko Epson.
If you go to the following link: https://www5.epsondevice.com/en/products/car_electronics/
in Crystal 32kHz and Crystal MHz sections, you can get several condensed datasheets and some overviews of some series.
One example: https://www5.epsondevice.com/en/products/crystal_unit/fa2016aa.html
Thank's a lot for your help!