In a further arrangement, the combined cross sectional area is less than 20% of {HEAD ~ the cross sectional area} of {TAIL ~ the hollow interior} 
of
In a further arrangement , the combined cross sectional area is less than 20 % of { HEAD ~ the cross sectional area } of { TAIL ~ the hollow interior }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL