I would like to discuss the mysterious subject of metal detector headphones. So far I have owned a Garret Infinium, and SD2000, a GP extreme, and an SD2100v2. Because I have bought them second hand, I always got a set of included headphones, and they had been ok or so I thought. I remember the instructions on the Garrett Infinium warning that Mono Headphones should be used at all times, as opposed to mono because they could operate properly within detector range But then with the SD2100v2, they came with a set of Koss UR30's, which I later found out are supplied new with the GPX5000's. When I