This was exactly the part I needed for my armstrong heater. I'm a homeowner, not a professional HVAC repair man and the instructions aren't as clear as I would have liked. I made some educated guesses and worked my way through it though. One area of frustration though: the hole pattern on the replacement mounting plate is a smaller footprint than the original board. Unfortunately they drilled the holes for one end of the board all the way at the edge which meant that the holes were blocked by the mating flange (which had the hole spacing of the original board). So I took the plate back of, drew 4 new holes and drilled them. It wasn't until almost the last step that I realized my new holes caused the board to get mounted so that it covered the holes needed to mount the transformer. I was too far in to disconnect everything & re-drill those holes too, so I have a partially mounted transformer now. Had the manufacturer drilled the holes in the right spot in the first place, this would have been a non-issue. The new board is smaller so there was no reason to put it all the way to the edge.