Fisher Gold Bug 2

The Gold Bug 2 runs at 71 kHz, and that number is the whole point: it is one of the most sensitive detectors ever built to tiny gold, the grain-sized pieces that almost everything else sweeps over. That sensitivity comes with a demand. It requires careful ground balancing, it will talk to you constantly in hot ground, and it needs a patient, slow swing. For prospectors working known patches where the easy gold has already gone, nothing else finds what it finds.