Stop in for a cup of coffee

So a question out to the collective coffee brain trust. After getting the opportunity to visit Gettysburg Battlefield (thanks again @ZMan67S ) my interest in what we speculate as a civil war defensive wall is renewed. As a result I want to purchase a metal detector and cruise the wall this winter. I know less about metal detectors than I know about Women. Any y’all ever used one? What are the features you need vs the ones ya don’t. I don’t live on the ocean so no need for submerge or salt water resistance. Any guidance would be much appreciated!