I just received a 8 X 9 coil today for my Silver uMax. Althought it was raining I had to give it a quick try. I went up to our very small town park turned it on and cranked up the sensitivity and had the disc. set really low, I got my first beep it sounded like a tin foil beep (a good beep both ways but not very loud). I dug down a good 6 inches and nothing in the plug, scanned the hole and still a beep, dug down about another inch or so and same thing. I figured that the target must be in the side of the hole so I enlarged the hole quite alot still same thing. I dug down some more and finally a screw top showed itself. I didn't have a ruler but my digger was at the top of the handle in the hole. By the time I dug the screw cap the rain was really comming down so I went home. I will test out my new (new to me) coil with my Silver uMax when the weather is nice again, I was realy impressed with the depth so far and want to see what it will do on coins/jewelry. Steve.