{HEAD ~ The front portion} of {TAIL ~ each push button} is also slidably guided to maintain the sealing pressure 
of
{ HEAD ~ The front portion } of { TAIL ~ each push button } is also slidably guided to maintain the sealing pressure
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH