Oxygen is also flowed into the tube through {HEAD ~ a pair} of {TAIL ~ oxygen injectors} 
of
Oxygen is also flowed into the tube through { HEAD ~ a pair } of { TAIL ~ oxygen injectors }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL