{HEAD ~ This invention} relates to piston seals, and specifically to {TAIL ~ a piston} having a seal formed thereon 
relates specifically to
{ HEAD ~ This invention } relates to piston seals , and specifically to { TAIL ~ a piston } having a seal formed thereon
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH