Hi
We at the European Center of Military History, we'v got one SPP offered from USA (kellydetector).
Unfortunately we didn't get the Manual and Head Set. So I went out just for a test and this little guy became almost insane while we were checking on a B-17 Bomber crash site.
It picked up a Cal .50 bullet (not the entire round - just the bullet) at 67 cm deep ...
In comparison to the past with Whites 2DB 5 and 6000 I think this SPP would pick up a metal part like a Jerrycan at something like 150 to 200 cm...