I did a search on micron conversions. 25 microns = 0.000984252 inches = 0.025 millimeters. That's pretty thin stuff.
80 microns = 0.00314961 inches = 0.08 mm.
Look at those numbers. Makes me so mad that the USA started to switch to the metric system when I was in school and then our stupid politicians changed their minds and decided we should stick with what we had. It would be too confusing to switch. Sorry about the rant.
I think the 25 micron thickness is for topping your embroidery when you are stitching something like towels. The heavier WSS stabilizer like the woven Vilene or clear type like Badgemaster I think are about 80 microns and this is what you would need to stabilize free standing lace items. So the larger the number, the heavier the WSS stabilizer.... Hope this helps...