The Fisher CZ-21 Underwater Metal Detector is a purpose-built, submersible detector designed for serious water hunters who need reliable performance in demanding environments. Built in the USA by First Texas Products, LLC under the Fisher Research Labs brand, this detector is engineered for underwater use in oceans, lakes, rivers, and surf zones where stability and audio clarity matter more than visual displays.
Operating on dual VLF frequencies of 5 kHz and 15 kHz, the CZ-21 is designed to handle a wide range of common targets encountered during water detecting, from coins and jewelry to other conductive metals. The detector uses an analog display and relies on audio feedback rather than visual target identification, allowing users to focus on sound cues even in low-visibility underwater conditions.
The CZ-21 offers three operating modes: Target-ID, Auto-Tune, and Pinpoint. These modes give users flexibility when searching different underwater environments or when switching between general scanning and precise target recovery. Manual ground balance allows the detector to be tuned for varying conditions, including mineralized sand and saltwater environments commonly found along U.S. coastlines.
Audio performance is a central feature of the CZ-21. It provides three-tone audio feedback—low, medium, and high tones—to help users distinguish between different types of targets without relying on a screen. Volume and sensitivity are both adjustable across ten levels, allowing hunters to fine-tune the detector to match their personal preferences and the surrounding conditions.
Designed specifically for underwater use, the CZ-21 is fully submersible to depths of up to 250 feet, making it suitable for scuba diving as well as shallow-water and surf detecting. The detector includes permanently attached waterproof headphones, eliminating the need for an external headphone jack and reducing potential water entry points. With a solid, sealed construction and weatherproof design, it is built to handle prolonged exposure to water.
Powered by four 9V batteries (not included), the CZ-21 is designed for extended detecting sessions. Its durable build and straightforward analog interface make it a practical choice for detectorists who prioritize reliability, underwater capability, and audio-based target response over advanced digital features.