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