In an attempt to find a mate to a JBL/ Dukane 5P360HP (2482) I purchased what was advertised as a 2482. Upon removing the back cover I noticed that the diaphragm is aluminum instead of the phenolic that I was expecting to see. Closer inspection reveals that the diaphragm screw spacing doesn't match the 2482 spacing. It appears that I have a 2440 with a 2482 back cover. Now, the ironical part of the story. I had two large JBL drivers with black wrinkle paint, the red seals intact and no foilcaps. They were sold to me as 375's. There was a noticeable difference in performance so I removed the seals and found that one was a 375 and the other was a Dukane 5P360HP. I sold the 375 and bought the 2482 to match the Dukane. Well, now I am back where I started with a pair of unmatched drivers. It does test one's sense of humor.