I have two spreadsheets (1 old & 1 new) I need to compare specific criteria. I need to search the old CSV of parts and compare to the new CSV of parts and tell me if we have old parts that match the dimensions of the new parts. The CSV headers in each are identical, but the part numbers have changed. I'm trying to find an easy way to have Excel tell me what the old part number is as a cross reference for the new part number. e.g. If new part 101 is 2x2x1 and old part numbers 609 and 845 are 2x2x1 then Excel list 609 and 845 as the result.

I used COUNTIFS to have it tell me how many match. I'm looking for a way to have it tell me what the associated old part numbers for those matches are. I know there's a way, but I haven't figured out how.