U/Water 1(cz21) CZ-21 Quick Silver – Premium Underwater Detector Whether it be Dry Land, Saltwater or Fresh Water, the CZ-21 Delivers. 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