The flexible sheets have a width which is greater than {HEAD ~ the width} of {TAIL ~ the insulating boards} so that longitudinally extending edge portions of the sheets project outwardly from the edges of the insulating boards 
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The flexible sheets have a width which is greater than { HEAD ~ the width } of { TAIL ~ the insulating boards } so that longitudinally extending edge portions of the sheets project outwardly from the edges of the insulating boards
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH