I replaced my metal coil screw on my Silver umax with a nylon one and it seems to have lowered the ED-120 just a teeny. I notice a lot more clicking around iron objects-just this week I found a set of keys that were more like tin than brass with a large steel ring that was well rusted laying in such a manner to cover the keys and it gave a "splat" with a kinda broken signal that I had apparently missed before. I also found an iron buckle for a strap that did the same. Even more noticeable are the signals near trash and the nickels really blast out now. I'm hoping it's true and that I've moved a step closer to approximating the Compadre in iron reject. I guess I should experiment with all metal and see if there's any difference there.