Hi Cudamark, its because the iron bleeds threw just below the silver range it quite often gives a good signal where you get silver coins and copper pennys. so if you have the two tone where do you put the line for iron if its lower like 20 then you have to dig all iron signals if you raise it youre missing half of the good targets you're cutting off half of the screen. The places where i hunt have thousands of years worth of iron and junk everywhere you can hardly move youre coil at times so digging it all like some sites is not possible, you'd be there all day just to cover ten square metres. So with two tone 90% of the iron sounds good yes you can turn sensitivity down or go in auto +3 but you will be scratching the Surface and might as well use your pinpointer. The hammies and romans can read on the left or the right of the screen but if there small or deep or even vertical they read all over the place its probably best to go by sound and not by the screen when looking for these. so thats why i said conductive might be better because each metal has a different tone and its easier to pick out the targets instead of the two tone when iron signals sound the same as good targets. ie targets can be missed, especially when you've heard pips squeaks and farts for the past 8 hours lol.