This is the wheel house channel that is shaped like an upside down "U". The brace is on the drivers side typically unless it is a CJ2A when the spare tire was on the drivers side then it would be on the passenger side. The brace is 10 1/2" wide and on the wheel house side is 11 1/8" long and the side panel side 4 3/4" long on the side panel side. Nice reproduction of a part that is typically rusted out.
Note: This does not fit the CJ5 and CJ6 models due to the wheel house is a little wider
1 Required per Jeep.