These are the new DetectorPro Gray Ghost Waterproof headphones for the Minelab Equinox metal detector series, 600 or 800. They are waterproof up to 30 feet.
The Gray Ghost Amphibian use a 50mm piezo and care constructed so the units offer a sound chamber surrounding the piezo which gets the buzzer to make better tones.
The volume control is the key for the Minelab Equinox Series Metal Detectors.
2 Year warranty on these headphones