Although this variation in size is desirable, for convenience it has been found that {HEAD ~ a narrower range} of {TAIL ~ sizes} from 10 to 1 microns or a narrower range from 5 to 1 microns with the maximum size 5 microns are adequate in most instances 
of
Although this variation in size is desirable , for convenience it has been found that { HEAD ~ a narrower range } of { TAIL ~ sizes } from 10 to 1 microns or a narrower range from 5 to 1 microns with the maximum size 5 microns are adequate in most instances
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH