{HEAD ~ A simple structure} is realized by using {TAIL ~ a common guide bore} for guiding the extension side valve body and the compression side valve body 
is realized by using
{ HEAD ~ A simple structure } is realized by using { TAIL ~ a common guide bore } for guiding the extension side valve body and the compression side valve body
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH