a cord shaped or tape shaped stopper having a first end portion and a second end portion, {HEAD ~ the first end portion} being fixed to {TAIL ~ the cover}; and 
fixed to
a cord shaped or tape shaped stopper having a first end portion and a second end portion , { HEAD ~ the first end portion } being fixed to { TAIL ~ the cover } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH