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