These sandals use a copper coil in the right foot, connected by USB port to a base unit strapped to your leg, to find metal objects in the sand up to 0.6 metres away. In theory.
The Price: $US60
Does It Work?: Yes, but not really. Only objects placed directly to the midsole triggered the metal detector. You'll know if you've found something by the tone, LED or, if it's in vibrate mode, feeling the rumble. Most of the time, however...
Did I Find Treasure?: Nope. I didn't find shit. The detector would beep when I put it against metal objects like keys within an inch, and even found the screws in my leg's titanium rod, but no dice in the real world actually hunting for booty.
Did Anyone Make Fun Of You for Wearing Them?: Not to my face, but I was still ashamed of myself.
The Verdict: Forget about it.
Too weak to find treasure.