ETA Caliber F06.412 Watch Movement

Manufacturer	ETA
Caliber Number	F06.412, F06412
Type	Quartz, battery-powered
COSC?	Possible, depends on watch
Thermo-Compensated?	Yes
Linges	11.5”’
Overall Diameter	25.6mm
Casing Diameter	26.20
Height	2.62mm (with 371 battery) or 3.22mm (with 395)
Jewels	3
Frequency	32,768 Hz
Accuracy Rating	+/- 10 seconds/year
Battery Cell Number	371 (SR920SW) or 395 (SR927SW) – see below
Battery Life	~68 – 94 months depending on the battery’s mAh
Low Battery Indicator?	Yes
Hands Count	3
Hand Sizes	1.20mm (hrs) / .70mm (mins) / .20mm (secs)
Functions	Central hours; central minutes; central seconds; date at 3:00
Hacking Seconds?	Yes
Mainplate Material	Brass
Country of Manufacture	Switzerland, Swiss made
Known Models	(Add your watches to the comments below…)

The ETA caliber F06.412 is a Swiss made high accuracy quartz (HAQ) movement with 3 jewels. This caliber is part of ETA’s Trendline family of quartz movements and is available as a HeavyDrive or PreciDrive (thermocompensated) movement.

The F06.412 replaced the F06.411 in 2018, and is still actively part of ETA’s quartz offerings.

Some of the topics covered in this caliber listing:

EOL:

You may see this movement listed as an EOL. EOL stands for end of life. This is a low battery indicator that is built into the circuit board to cause the second hand to jump every 4 seconds when the battery is low on juice.

Battery Life:

The F06.412 has rather long battery life when using a higher mAh cell. When using a 40 mAh cell, the battery life can be up to 68 months. With a 55 mAh battery cell, the battery lasts up to 94 months. Note that you cannot simply install a high mAh battery unless your watch is designed to handle the increased thickness. The 371 cell has a diameter of 9.5mm no matter what the mAh is, but the 40 mAh cell is only 2.1mm tall compared to the 55 mAh cell at 2.7mm. Usage will depend on the watch model and design of its case.

Crown/Stem Removal:

To remove the crown, the crown should be in neutral position (against the case). Look for the stem release hole on the movement near the crown There is a small arrow pointing to it. Putting the crown to date setting position should reveal a button in the hole that you can gently press with your tool to release the stem. Do this carefully and do not press too hard. If you damage the stem release mechanism, there doesn’t seem to be a way to fix it since it’s encased in plastic.

Date Changing:

The F06.412 has a quick set date feature with the crown in the second position. The date flip on a running watch is considered semi-instantaneous. Therefore, don’t be alarmed if there is lag from the time the date engages and flips over at midnight. The total time is takes for the date to flip can be up to an hour. If the date on your watch doesn’t flip when the hands pass midnight, it doesn’t necessarily mean your watch needs serviced or has an issue, it could simply be how the hands were installed by the manufacturer.