Preferably, {HEAD ~ the film} has {TAIL ~ a total thickness} of from about 3 to 20 mils 
Preferably , { HEAD ~ the film } has { TAIL ~ a total thickness } of from about 3 to 20 mils
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH