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