Hammacher Schlemmer has designed a $60 pair of sandals that contain a 9 volt battery and copper wire. If any change or metal is discovered while walking around the anklet pack tied to the beach roamer’s leg vibrates. The change or metal could even be 2 feet below surface. If you spend a lot of time walking around the beach, I highly recommend picking up a pair of these. You never know if a treasure chest could turn up.