{HEAD ~ a fastening surface} positioned opposite {TAIL ~ the engagement surface} and configured to receive the internal component, the fastening surface having a shape in accordance with a portion of the internal component, wherein the shape of the fastening surface is different from the shape of the engagement surface 
{ HEAD ~ a fastening surface } positioned opposite { TAIL ~ the engagement surface } and configured to receive the internal component , the fastening surface having a shape in accordance with a portion of the internal component , wherein the shape of the fastening surface is different from the shape of the engagement surface
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH