Honestly, I just wanted the 4 pin socket at the end to fit to other equipment. It's damn hard finding these things. What do you call it anyway? Long story short, I found this listing via a google image search. The photos were clear enough I could compare to what I had, and I could order it. I'm not using it for a fan, and I'm not using the flat adapter side. I'm just custom wiring the small adapter side into a furnace in hopes I can fix it for the totally fair price offered on this site rather than have to argue with a contractor who will just want $10,000 to replace the furnace rather than fix the piece that's broken. So yay!