I just traded for a AT Pro. Really think I am going to like it. Definitely love the iron audio. With my old machine if I ran with low disc. trying to find gold rings. old bottlecaps always sounded like a good coin. With the Pro, I dont have this problem. I was curious if anyone has used the 4.5" coil much. How deep is it? Thought it would be good for hunting trashy construction sites. Thanks, Mark