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