{TAIL ~ The diffuser elements} have an average space therebetween of {HEAD ~ 50 to 300 micrometers} 
{ TAIL ~ The diffuser elements } have an average space therebetween of { HEAD ~ 50 to 300 micrometers }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD