A. You'll first need to determine what kind of pipe you have, which should be relatively easy just by looking at the pipe. Most old-fashioned radiators are cast iron, but some newer models may be stainless steel, aluminum, or ceramic-coated. You'll want to measure across the pipe and then compare that measurement with the inside diameter of the escutcheon to be sure it will fit around the pipe. For more help, check out the video below as we explain some of the differences between IPS and OD size.