Over the years we have had numerous people ask if we have different size nylon or polyester mesh sizes because they wanted a size in between the mesh sizes we carry. We recognize that some application are critical and that 3 microns can make a difference. But we have also found that many applications are not as critical and 10 to 20 microns will not impact the results. We have included these two images to help understand just how small a micron is and hopefully help people determine just how critical those specification need to be. If we list a nylon or polyester mesh on our website and it is close to your application, and your application can be flexible, it can save a good deal of time and money by using stock sizes rather than special ordering the exact size. I hope this helps.
Below is a tape (scaled on the screen as best I can) that give some indication of a micron in comparison to a cm.
This is a representative blown up view of the edge of standard copy paper. Now you can compare what 1, 5, 10 and 20 microns are to the thickness of a sheet of paper.