Rather, the closure is such that {HEAD ~ the free exchange} of gas between {TAIL ~ the internal volume} of the capped swab transport tube assembly and the external environment is allowed 
between
Rather , the closure is such that { HEAD ~ the free exchange } of gas between { TAIL ~ the internal volume } of the capped swab transport tube assembly and the external environment is allowed
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH