Metal detector EPX-7500 Long range king EPX-7500 Long Range King Metal Detector [1]INTRODUCTION: 1.Long Range King System is an advanced Metal Detector System utilizing advanced FORWARD GAUSS technology that is both an audio and visual detector. 2.This metal detector was first used in the field in 1984 and the FORWARD GAUSS technology that it uses has proven to be (by far) the most successful. 3.This system was originally developed for professional archeologists and treasure hunters and has been used on many stations.