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 removeable 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, this adds a great amount of shear strength as in a severe drop on a rock (anyone ever do that?). The bolt holes are .625" (5/8) so you can use a real sized bolt. .25" HR P&O Steel Plate. Sold each.