I'm doing a project where I need some filters. I found some reasonably priced ones on the internet but I have no idea how to tell which size is which. I'm looking for the size that filters out the smallest particles. The sizes available are 0.45 microns and 0.2 microns. I know this may seem like a pretty dumb question but which way do these numbers go, it seems to me that the 0.45 micron filter would be the finest one. I'm lost in space on this one & need to get the filters soon. If anyone can help I would appreciate it. THANKS!!!

0.45 microns is a larger size than 0.2 microns.

0.2 micron filter will be the finest one. this is a measurement of the space between the mesh fibres.

 

the smaller this size the finer the filter.

Thanks alot!! I was thinking that 0.2 microns meant 2 tenths & 0.45 meant 45 hundrenths, figuring that 0.45 was smaller. That's where I was getting messed up. I still don't seem to get it but at least I know which one to get!! Thanks again!!

2 tenths is 20 hundredths, which is smaller than 45 hundredths

I was terrible in math when I was in school and that was 34 years ago. As you can see I haven't gotten any better at it.