Fisher CZ21-8 Underwater Metal Detector Saltwater or fresh water - submersible up to 250 feet - dual frequency fourier domain signal analysis Touch-button., vco no motion, precise pinpointing - easy manual ground balance - high performance in mineralized soil All-metal auto-tune mode - large target alert / faint target audio boost 3-Tone Audio Target ID - Removable Control Housing for Belt Mount - 8 and 10 Coil Options - Operating Frequency: 5 and 15 kHz Recommended for: beach hunting, shallow water, lake /surf, diving