{TAIL ~ An annular protrusion} axially extends from the valve body and is symmetrical about {HEAD ~ the orifice} 
{ TAIL ~ An annular protrusion } axially extends from the valve body and is symmetrical about { HEAD ~ the orifice }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD