{HEAD ~ The width} of {TAIL ~ the valve member} is smaller than a peripheral dimension of the openings 
of
{ HEAD ~ The width } of { TAIL ~ the valve member } is smaller than a peripheral dimension of the openings
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH