Gary,
A few weeks ago, while hunting a tot lot, one of the locals asked if I knew anyplace he could rent one of those things. I told him, "I doubt it, why did you lose something?" Turns out he lost his platinum wedding band while putting in a flower bed. So we went over to the suspected area, I whipped out the 70 and got to work. The flower bed was only about 2-1/2' wide and maybe 20' long ,so this wasn't going to take long. The first hit was a strong 20, about 4" down. Big screw top. I slowly work my way down the bed. Another hi-tone hit - a lousy nail.
The last 5 feet. Uh-Oh, could be trouble. But NO - a strong 12-14. Bingo. Only down about 4". This was a wide, thick men's platinum wedding band. Didn't ask about purity. So his wife says to him, "Well, I guess we're married again!" So all is sweetness and light at their household for now.