Hello Skiwhiz; I'll try to answer your guestions.When you select pinpoint mode it will sound off when your over the target,but the detection area is large on shallow or large targets.If you push the button agin it will narrow the area of detection making it easier to center the target in the center of the coil,you can keep narrowing it if you wish.It will become apparent when you try it. The depth appears to be good the deepest coin was a clad dime about 7 inches,the id is good but on deeper coins it tends to bounce around a little.Agin takes a little use to understand what it;s telling you.I used the DD for about an hour changed to the 10" I like the 10 better.The 8" coil is the one I prefer.I also like The 4" coil for trashy areas and close to fences and playgrounds.The batteries seem to last longer than the 3300 but I use rechargeable so can't really say. Some one can probably explain the pinpoint better.Hope this helps.