This 1.5" hole plate can be used however you see fit, we see them being used primarily as rocker and cage joining attachment plates. When mounting a cage securely through the floor use 2 (1 for either side) and place the tube at least 2/3 of the way through, weld both inside and out, this adds a great amount of shear strength as in a major side impact. The bolt holes are .625" (5/8) so you can use a real sized bolt. .25" HR P&O Steel Plate. Sold each.