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