In this extended portion 11c is formed {HEAD ~ ribs 11h} formed on both side edges and {TAIL ~ an extended piece 11d} 
formed on
In this extended portion 11c is formed { HEAD ~ ribs 11h } formed on both side edges and { TAIL ~ an extended piece 11d }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL