I have a FISHER LF-990D Discriminatar VLF. I have one but I need to put a new 9volt plug in it. So I have never used it. What is it best for. I think it is kinda like the Gold bug I hope so. I need a Gold finding M.D. I got it after my step Dad died it was his. We only used it twice. So I don't know how good it works. My mom bought it for him in the 80's when I was a teenager. I think it cost about two or three hundred dollars at the time. I have two paddles big & small.