a stiffener defining an opening in a central portion thereof and having front and rear ends, the stiffener having an locking hook close to {HEAD ~ the front end} along {TAIL ~ a first side} of the stiffener 
a stiffener defining an opening in a central portion thereof and having front and rear ends , the stiffener having an locking hook close to { HEAD ~ the front end } along { TAIL ~ a first side } of the stiffener
OTH OTH OTH OTH OTH OTH OTH 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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH