For {HEAD ~ a given source pressure}, the loose fill insulation has {TAIL ~ a characteristic pressure drop} for a given density 
For { HEAD ~ a given source pressure } , the loose fill insulation has { TAIL ~ a characteristic pressure drop } for a given density
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH