AWD. Center c'member nut. A Nut used to retain the Frame Side Member to it's mounting point. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Aperture Panel. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Floor Pan CrossMember. Center c'Member. Floor Pan CrossMember. Frame Side Member. Rail Assembly. UniSide Assembly. Included with: Center CrossMember, Center Floor Pan, Rear Rail Assembly.