A windup/unwind mechanism can be connected to the roll and is capable of locking in selected positions for selecting {HEAD ~ the tension} of {TAIL ~ the barrier member} 
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A windup / unwind mechanism can be connected to the roll and is capable of locking in selected positions for selecting { HEAD ~ the tension } of { TAIL ~ the barrier member }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL