Poring over the Internet the past few weeks looking into getting a PI machine. I've been waiting for a company's new board to come out for an affordable DIY machine. Instead, I stumbled across a series of machines from Whites that sounded perfect for what my intended uses are, the TDI. Found only one legit listing for a lightly used TDI SL. Contacted the seller and working out delivery details and such, should have it in about a week to 10 days.
Blew my mind even I found out PI machines when set correctly can tune out targets either by size or conductivity. They can also blast through trash as it would ground mineralization and pick out the targets underneath. I'm thinking the parks in my area that were undetectable before due to a pull tab and foil blanket will open up to the PI machine and maybe get those really old deep coins that vlf detectors can't touch. Hoping for the best!