Hairball,
I really didn't find the dri-rod incabable of altering the humidity. With the safe door closed, I was able to achieve a localized zone of dehumidified air. I kept a digital gauge inside the safe - when I opened it - it was consistently indicating something in the 30-40% range in Hawaii - where the humidity where I lived, Kaneohe Bay, was typically twice that. So, I really felt the dri-rod was doing its job - after I bought two and placed them inside the safe. It was pretty obvious that I didn't have the rusting problem like I would have had I had no means of dehumidifying the area otherwise. Granted the safe was not air tight by no means but with the door closed, I believe that it had enough of a localized zone of control to be effective. What can say categorically is my weapons were not rusting! That was plenty good enough for me. I think for climates less demanding than Hawaii, folks should have correspondingly better results.