Get a good Pulse Induction (PI) Detector with a large Coil, or a Two-Box Detector.
Both Technologies have been around for a long Time and they are known to actually work, no black magic needed.
Try to borrow or rent a good PI Detector and try it, dont spend lots of cash on a magic "black box".
Mineoro Products are expensive and there is no real Proof that they actually work - so this would be a high risk investment.

Yes for a PI detector, the only machine that can detect gold of some weight for sure.

πάρτε κανέναν ραβδοσκόπο, γιατί από τα μηχανάκια δεν βλέπω προκοπή!!! :razz::razz::razz:

The “box” as you call it is commonly known as the vagina a part of the female genital. Placing money in one of these is commonly known as “prostitution” which in my country is illegal on a mine site. Placing your money in one of these “BOXES” is commonly known as an affair and can cost you deeply. Good luck in finding that “OLD BOX”
Happy prospecting
Ernie