I still have my Depth master that I bought back i the 80's. It was designed to be used with about any detector. It amplified weak signals and muted loud signals from junk. They also made head phones with it in them. I used it mainly with my old Tek 9000. It still works. I believe it uses one AA battery if I remember right. It was plugged into the head phone jack on the detector and then you plugged your head phones into it. I attached mine to my detector with a strip of Velcro.
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