I hunt civil war campsites littered with square nails and ive tried the minelab safari,teknetics t2 se but they give good audio and id on the old sqauare nails so i bought an at pro yesterday because i had heard it was really good at discriminating in the old sites. All i can say is "WOW",i went out this morning and put discrimination at 40 and dug 3 eagle buttons and a bunch of other stuff that i had missed with the other two detectors i mentioned. Big thumbs up to the at pro and it is without a doubt the best disriminating machine i have used. Awesome machine!