It is an object of {HEAD ~ the invention} to provide {TAIL ~ an integrally formed piston} and seal therefor 
to provide
It is an object of { HEAD ~ the invention } to provide { TAIL ~ an integrally formed piston } and seal therefor
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH