{TAIL ~ a valve body} defining a main valve cavity and {HEAD ~ a smaller diameter metering valve cavity}, with a narrow interconnecting passage between them, 
{ TAIL ~ a valve body } defining a main valve cavity and { HEAD ~ a smaller diameter metering valve cavity } , with a narrow interconnecting passage between them ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH