One of the one way valves is located on the inside of one side of the barrier bag, and the other of the one way valves is located on {HEAD ~ the outside} of {TAIL ~ the other side} of the barrier bag 
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One of the one way valves is located on the inside of one side of the barrier bag , and the other of the one way valves is located on { HEAD ~ the outside } of { TAIL ~ the other side } of the barrier bag
OTH OTH OTH OTH OTH OTH OTH OTH OTH 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 OTH OTH OTH OTH