{TAIL ~ an outer tube} having first and second ends and {HEAD ~ a lateral inlet} near said first end, 
{ TAIL ~ an outer tube } having first and second ends and { HEAD ~ a lateral inlet } near said first end ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH