A piston pump 17 wherein {HEAD ~ said wear pad} is made of {TAIL ~ a polyethylene} 
is made of
A piston pump 17 wherein { HEAD ~ said wear pad } is made of { TAIL ~ a polyethylene }
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL