Preferably, {HEAD ~ the annual chamber} extends from the inlet port to {TAIL ~ an axially opposite end} of the first hub collar 
extends to
Preferably , { HEAD ~ the annual chamber } extends from the inlet port to { TAIL ~ an axially opposite end } of the first hub collar
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH