These are Reinforcement Plates to box the rear of your FJ40, they are .1875" (3/16) thick Steel Plate. Made to strengthen an inherently weak area on an FJ40, opinions differ on whether or not Boxing the frame should be done so do your research. We believe the frame should be stiff and the suspension should be doing the flexing. Flexing the frame loosens the rivets and slowly tears it apart. This comes with a 1.75" x .120" DOM replacement crossmember with 4 predrilled placement options, one of the holes is at the stock position and the others are spaced 3" on center, one in front and 2 behind the stock position. If you are adjusting your WB way back we would recomend 2 Crossmembers to retain the structural rigidity gained by the frame boxing itself and the Crossmembers provided are long enough to allow mounting through the existing frame also (just drill 1.75" holes through the frame using the Plates as a guide). These are designed to fit within the frame itself so you do not have to remove the tub to install, however you do have to remove the factory Crossmember and mounting plate and reposition the rear brake line. The short angled plates are made 1/8" long to allow for movement that has already occured, comes with 5 plates, 1 crossmember, & 1 pair of Shock Brackets. Welding Required!