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