ETA Caliber F06.105 Watch Movement

Manufacturer	ETA
Caliber Number	F06.105, F06105
Replaces Calibers
Type	Quartz, battery-powered
Linges	11.5”’
Overall Diameter	25.6mm
Casing Diameter	26.2mm
Height	2.5mm thick
Jewels	Three (3)
Frequency	32,768 Hz
Battery Cell Number	371 (SR920SW) or 395 (depends on the watch case design)
Battery Life	~68 to 94 months (depending on the battery’s mAh)
Hand Count	3
Hand Sizes	1.20mm (hrs) / .70mm (mins) / .20mm (secs)
Functions	Central hours; central minutes; central seconds (also available as a 2-hander without seconds)
Other Features	Low battery indicator (EOL)
Hacking Seconds?	Yes
Country of Manufacture	Switzerland, Swiss made (V8)
Known Models	(Add your watches to the comments below…)

The ETA caliber F06.105 is an affordable time-only quartz movement with 3 jewels. The F06.105 is essentially the no-date version of the ETA F06.115. It is a true no-date movement without a phantom date position.

This caliber is part of ETA’s entry level Trendline series of movements. Based on ETA official tech documents, this caliber has been on the market since at least November 6, 2019.

Some of the topics covered in this caliber listing:

HeavyDrive:

This caliber is equipped with ETA HeavyDrive which is essentially a sophisticated anti-shock technology for a quartz watch. In ETA’s own words:

“HeavyDrive technology enables intelligent shock management for the second’s hand and is opening up new possibilities for hand design.” –Source

Battery Life:

The F06.105 has fairly long battery life when using a higher mAh cell. When using a 40 mAh cell (371), the battery life can be up to 68 months. With a 55 mAh battery cell (395), the battery lasts up to 94 months.

Note: 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.

How to Change the Battery:

The F06.105 takes battery number 371 (aka SR920SW) or 395 low drain 1.55 V.

Replacing the battery in your F06.105 watch is straightforward. As pictured, place your tool between the battery and the arm that holds it in place (#2 in the image below). Gently pry the arm back and the battery should lift up. Be careful not to bend of break off the arm that holds the battery in place!

To install the new battery, do the process in reverse, but make sure the battery is placed under the lip first (#3 in the image above). If you install a new battery and the watch doesn’t function properly, it’s possible that the battery is bad. Always try a new battery before giving up.

Crown/Stem Removal:

To remove the crown, 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.