Hay Canewrap,
The " Iron ID " switch replaces the frequency adjust switch.
It's a three position switch.
The center possition is off. Off is just like an Eldorado with out
a frequency adjust switch.
The left position is called " Iron Blank ". In this position, the small
iron is desccriminated out. Aluminum and some other stuff will crackel.
In the right position, small iron will have a low tone. Aluminum will have
a low tone with some crackling going on. A pull tab will be a broken
sound between the low tone and the regular tone. The stuff that is higher
conductors will have a regular tone.
It is helpful, but will not out perform the Eldorado. Just a little more convient.
Happy Hunting,