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