{HEAD ~ The contoured body cross section} is commensurate with {TAIL ~ the contoured wall cross section} for inserting and keying the housing into the receptacle 
is commensurate with
{ HEAD ~ The contoured body cross section } is commensurate with { TAIL ~ the contoured wall cross section } for inserting and keying the housing into the receptacle
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH