Additionally, the housing 12 includes {HEAD ~ an inlet} 15 for receiving {TAIL ~ an assist gas}, which is typically air 
for receiving
Additionally , the housing 12 includes { HEAD ~ an inlet } 15 for receiving { TAIL ~ an assist gas } , which is typically air
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH