Compare 20 micron thickness to gold filled?

The thickness of gold on a gold-filled watch varies, including on the same watch, as a gold-filled finish can vary in thickness. But generally, a gold-filled finish will be about 20-40 microns thick.

A 20 micron gold-plate finish is a bit thinner than most filled-gold finishes but is more uniform. A 20 micron gold-plate finish will wear a long time and compares well with a gold-filled finish.