Thus, this valve mechanism can open and close {HEAD ~ the air communication portion} in {TAIL ~ a reversible manner} 
in
Thus , this valve mechanism can open and close { HEAD ~ the air communication portion } in { TAIL ~ a reversible manner }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL