This is an old thread, but to me the GPX 4500 is new thanks to Rob ..... Took it out today for the first time and found a little small .30g nugget under some tree roots in an old wash with ancient river beds and coming fron an SD 2200D and a GP3500 I can say today I dug holes I never had dug in the past, mostly lead, but I swear I never dug (2 feet) deep holes before to find lead .......