“These are the sandals that can detect metal while you walk, allowing you to find buried artifacts while strolling the beach. A copper coil built into the right sandal is powered via a battery pack that straps to your calf. Using beat frequency oscillation technology, the ring creates a magnetic field; when a metal object is underfoot–up to 2′–it distorts the field and the battery pack alerts you to the presence of metal using a flashing red light and either a gentle vibration or a clearly audible buzz. Requires one 9-volt battery (not included)–provides up to six hours of use. The sandals have non-skid soles and polyurethane foam footbeds. Black. Sizes M (Men’s 7 1/2-9, Women’s 8 1/2-10) and L (Men’s 9 1/2-12, Women’s 10 1/2-13). (1 lb.)”

Check them out for yourself: http://www.hammacher.com/publish/76779.asp