In these arrangements, {HEAD ~ the threaded collar} may further include {TAIL ~ a tubular body} with a hollow interior to permit fluid flow though the collar 
In these arrangements , { HEAD ~ the threaded collar } may further include { TAIL ~ a tubular body } with a hollow interior to permit fluid flow though the collar
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH