Yeah mine says automatically tunes, etc. but don't believe it.
If you get falsing, where it occasionally goes off, and no object around, then it is picking up ground mineralization. This indicates it is set to a too sensitive setting. Mine came this way from the factory... go figure. <img src="/metal/html/tongue.gif" border=0 width=15 height=15 alt=":b">
To adust, take off the four outer back screws, turn the modular screw adjustment full counter-clockwise, hold the unit with tip pointing up, and slowly adjust the screw slot clockwise until it goes off. Once it goes off, turn it slightly counter-clockwise and then test by turning the unit 90 degrees either left or right. If it doesn't go off you should be adusted. The unit is made to reach a nickel at 3/4 of an inch.
A lot of adjusting for a unit that doesn't need adjusting.. <img src="/metal/html/lol.gif" border=0 width=15 height=15 alt=":lol">