Better photo of the mouse, dismantled one, and closer look on the microswitches, for those who were interested.

I unfortunately don't know the model name, because I have removed and lost the information tag, which was on the mouse's belly, because it was scrubbing the mousepad. But it looks exactly like the "Mitsumi Serial Mouse (ECM-S3101 model)" mentioned here . There is some, maybe insignificant, "CMKM-P3X...

I have an old Mitsumi serial 2-button ball mouse, which is very silent. It has a different type of microswitches than recent optical mouses (it's smaller with round "button"). Pitty that mouse manufacturers do not declare power consumption and noise levels. I'm not sure which one eats less watts - s...