Base port 10 may be connected to {HEAD ~ a vacuum} to facilitate {TAIL ~ fluid pull} through 
to facilitate
Base port 10 may be connected to { HEAD ~ a vacuum } to facilitate { TAIL ~ fluid pull } through
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH