Was the ATX designed and marketed to be sold to and be used with AT PRO, AT PRO GOLD or the GTI 2500 detectors? It's given that the ATX is a multi-freq PI and the others are VLF variations, but what does the ATX bring the detecting game, other than hopefully small gold in deeper holes! Typically, excellent VLF machines already do excellent discrimination and reasonably funky dirt! But if you like to dig like a gopher, the ATX should be the ONLY detector yøu need ... maybe! But heck, any respectable metal detectorists owns 2-3-4+ machines ... salty water & beaches to dry sand to black sand to clay to mineral rich rock and dirt to patchy-iron ground to the large open fields where Woodstockers & 1st Atlanta Festival types lost their clothes and buttons, many pop tops and a few fiery butane lighter torches, and maybe a few silver and gold teeth, along with the small metal hook-like bra quik-snaps! Yeah, I was at the 1st Atlanta and West Palm Beach Festivals and the grounds were covered with everything one might lose, on purpose or not! sorry I got carried away off-topic. Billy