This 2.0" Square hole plate can be used however you see fit, we see them being used primarily as crossmember joining attachment plates. When mounting a crossmember of a fixed type these are the way to go, place the tube at least 2/3 of the way through the square hole, weld both inside and out then weld to frame as desired, this adds a great amount of shear strength as in a severe drop on a rock (anyone ever do that?). A50 Steel Plate. Sold each.