{TAIL ~ an extension side pressure control valve} provided at {HEAD ~ the extension side bypass flow passage} and adapted to be opened by receiving a pressure in the extension side bypass flow passage, 
{ TAIL ~ an extension side pressure control valve } provided at { HEAD ~ the extension side bypass flow passage } and adapted to be opened by receiving a pressure in the extension side bypass flow passage ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH