Personally, I would not recommend a PI machine unless you're real familiar with salt water hunting on popular beaches; otherwise you'll be digging deep trash most the time. [If you go w a PI machine buy the White's TDI; deepest machine out there.] If you're looking for one of the least expensive saltwater machines, go with the NOX 600 that is multi-frequency and you can discriminate out a lot of trash. Advise wired water-proof headphones. Nox 800 my next choice. Excal my next choice (takes long time to know sounds) followed buy the most expensive, but best machine; CTX 3030. The NOXs are very complicated machines and even though they say in 3 button pushes you can be off and running...best advise is that you first read Andy Sabisch's Equinox book several times and work w the machine at least a few weeks to modify to your specific needs. If you take a NOX to the beach for the first time and expect to find a lot...you'll be surprised and not in a good way. Best to take time to learn basics of the machine, whichever one you choose. Happy Hunting