The Fisher CZ-21 is a highly regarded underwater metal detector designed for enthusiasts and professionals alike. This review explores its key features, performance capabilities, and overall user experience to help you determine if it’s the right tool for your treasure-hunting adventures.
Contents
What the device was designed for?
The Fisher CZ-21 is a professional-grade underwater metal detector designed for serious treasure hunters. It features dual operating frequencies, allowing for enhanced versatility in various aquatic environments. This device can be submerged to depths of 250 feet, making it ideal for both freshwater and saltwater exploration.
The CZ-21 employs a specialized signal processing approach that ensures reliable performance in brackish and seawater. The lower frequency of 5 kHz is effective for detecting a wide range of objects, including larger metal items like coins and relics. In contrast, the higher frequency of 15 kHz enhances sensitivity to non-ferrous metals, particularly smaller targets, such as gold rings and small jewelry. This dual-frequency capability allows users to adapt their search strategies based on the types of objects they are looking for and the conditions of the water.
| Model | Fisher CZ-21 |
| Weight | 8” Coil 5 lb, 10.5” Coil 6 lb, 5” Coil 5.4 lb |
| Length (Adjustable) | 30”- 50” |
| Batteries | 9 Volt (4) |
| Headphones | Included |
| Warranty | 2 years |
| Operating Principle | VLF |
| Standard Searchcoil | 10.5’’ Concentric |
| Operating Frequencies (kHz) | Dual, VLF Search 5 KHz and 15 KHz |
| Water resistance | Yes |
| Submersion Depth | up to 250 feet |
| Discrimination | Yes |
| Ground Balance | Yes |
| Audio Threshold | No |
| Electronic Pinpointing | Yes |
| VDI (0 to 99 scale) | No |
| Build-in flashlight | No |
Last update on 2024-11-01 / Affiliate links / Images from Amazon Product Advertising API / Source: Amazon Affiliates
Review
The shaft
Ergonomic Design and Adjustability of the Fisher CZ-21 Shaft
The Fisher CZ-21 features a T-shaped shaft designed to minimize weight while maximizing user comfort. It consists of two sections: the upper shaft is made from lightweight aluminum, while the lower section is constructed from impact-resistant carbon, ensuring durability without compromising portability. This combination not only reduces weight but also ensures the detector withstands accidental drops and rough handling.
The two shaft sections connect using a single spring button, allowing divers to quickly adjust the metal detector’s shape underwater. This design enhances maneuverability, making it easier to navigate tight spaces or shift between search angles. Additionally, the single spring button for connecting the shaft sections allows for easy disassembly and storage, making transportation more convenient.
Customizable Length and Comfort Features
The shaft length can be adjusted to suit individual user preferences, thanks to multiple adjustment holes in the upper section. This flexibility accommodates users of different heights, ensuring comfortable operation whether searching underwater or on the beach.
For added comfort, the armrest is lined with porous plastic, which provides a secure grip and stabilizes the forearm during prolonged use. The device also features a large handle with a non-slip coating, further enhancing comfort and control while operating the detector. The T-shaped shaft design provides optimal balance, ensuring that the weight is evenly distributed for less strain on the user’s arms and shoulders during use.
To streamline the treasure-hunting process, the control unit can be attached to a user’s belt. When submerged, the control unit is positioned on the upper shaft, but during beach hunts, it can easily be hung on the belt, reducing the overall weight of the device. This belt attachment feature allows users to keep their hands free for more agility while hunting, enhancing overall efficiency.
The Fisher CZ-21’s adjustable size ranges from 30 to 65 inches, allowing users to find their ideal length. The assembled detector weighs approximately 5 pounds (2.8 kg), depending on the search coil type, making it manageable for extended use. The lightweight design makes the Fisher CZ-21 suitable for all-day use, especially beneficial for those engaging in long treasure-hunting sessions.
The coil
Standard Package Contents of the Fisher CZ-21
The standard Fisher CZ-21 package includes the Fisher 10.5’’ concentric search coil, constructed from durable plastic and designed to operate effectively at significant depths. This coil features a non-detachable cable, as it is specifically engineered for deep submersion. The same applies to the included headphones, which are designed for underwater use.
It’s important to note that a protective case for the coil is not included in the metal detector package. If a protective case is needed, it should be ordered separately.
Versatile Search Coils
In addition to the standard coil, there are various other search coils of different sizes and specifications available for use with the Fisher CZ-21, providing users with options tailored to their specific needs and preferences.
Advanced VLF Technology
The Fisher CZ-21 utilizes VLF (Very Low Frequency) technology, allowing the device to operate on two frequencies simultaneously: 5 kHz and 15 kHz.
The 5 kHz operating frequency is ideal for deep searching and exploring various prospective areas. When using this frequency, users can effectively detect larger-sized targets, ensuring nothing is overlooked. For prospecting gold nuggets, users can switch to the 15 kHz frequency, which enhances sensitivity to smaller targets. This setting ensures that even the tiniest gold nuggets, closely woven chains, and rings are detected, making it an invaluable tool for treasure hunters seeking fine jewelry or valuable small items.
Headphones
Underwater wired headphones are included in the Fisher CZ-21 metal detector package, ensuring users can hear audio signals clearly while submerged. These specialized headphones are designed for underwater use, providing superior sound quality and reliability in challenging environments. The waterproof design ensures they function optimally even when fully submerged, while their sound isolation feature allows users to focus on the detector signals without background noise interference.
By using these headphones, treasure hunters can easily identify and respond to target signals, enhancing the efficiency of their searches. Many models also come with adjustable straps for a secure and comfortable fit during extended use. Additionally, the headphones are built to withstand the harsh conditions of saltwater and freshwater environments, prolonging their lifespan. The inclusion of these headphones in the package highlights Fisher’s commitment to offering a complete and user-friendly metal detecting experience.
The battery
The Fisher CZ-21 metal detector is powered by four 9 V batteries, providing up to 35 hours of continuous operation. Typically, a single set of batteries is sufficient for 4 to 5 treasure-hunting trips, making it a reliable choice for extended outings. The use of 9 V batteries is common in many professional-grade metal detectors due to their compact size and reliable performance. The batteries are housed in a special waterproof battery holder, ensuring protection from the elements.
However, it’s important to note that replacing the batteries requires a screwdriver to open the holder. If you find yourself in a situation where a battery replacement is necessary and do not have a screwdriver or a coin handy, your treasure-hunting adventure may come to an unexpected halt. Therefore, it is advisable to carry a small screwdriver in your gear to avoid any interruptions during your search for hidden treasures.
Waterproofness
The Fisher CZ-21 metal detector is designed for underwater treasure hunting, making it suitable for deep searches at depths of up to 250 feet (76 meters). This remarkable depth capability enables users to explore a wide range of underwater environments, from shallow lakes to deep ocean floors, increasing the potential for discovering valuable treasures.
The control unit
The Fisher CZ-21 metal detector features a user-friendly control unit, designed for simplicity and efficiency, especially in underwater environments. Like most underwater detectors, it has minimal settings, with no display to navigate.
On the control unit, you will find four potentiometers and one button. These potentiometers allow users to adjust key settings: device sensitivity, volume (which also powers the device on), ground balance, and discrimination.
Sensitivity Adjustment: The sensitivity is controlled via the SENS switch, with levels ranging from 1 to 10. A higher sensitivity setting enables the device to detect objects at greater depths. This same potentiometer also serves to check the battery charge level, ensuring you are aware of your power status before diving.
Ground Balance: The GROUND potentiometer is used to adjust the ground balance, which is crucial for accurate readings in varying soil conditions. Users can choose between pinpoint mode or ‘all metal’ mode to perform this adjustment effectively.
Pinpoint Function: The pinpoint button switches the metal detector to ‘all metal’ mode, allowing users to locate targets more precisely. The volume of the sound increases as you approach the target, providing an intuitive way to hone in on potential finds.
Search modes
The Fisher CZ-21 metal detector offers three distinct search modes, each designed to optimize performance for underwater treasure hunting. These modes include:
1. Dynamic Mode with Discrimination: This mode operates without a threshold tone, allowing users to discriminate between different types of metals. It’s ideal for locating valuable targets while ignoring unwanted metals.
2. Dynamic Mode ‘All Metal’ with Threshold: In this mode, the detector responds to all metal types, producing a continuous tone to indicate the presence of metal. This feature is particularly useful for locating buried objects in areas where you want to ensure no targets are overlooked.
3. Static Pinpoint Mode: This mode is designed for precise target location, allowing users to hone in on specific finds after detecting them in dynamic mode. It’s particularly effective when treasure hunting in cluttered environments.
In addition to these modes, the Fisher CZ-21 features adjustable sensitivity levels, a ground balance function, a threshold tone, and a pinpoint mode that enhance the detector’s overall performance.
The threshold tone is exclusive to the ‘all metal’ mode. To activate it, simply switch the DISC potentiometer to the AUTOTUNE position, enabling more accurate detection of metals while maintaining a steady audio tone.
Tones
The Fisher CZ-21 metal detector features a three-tone sound identification system, which is crucial for effectively distinguishing between target types. The low tone indicates ferrous targets, while middle and high tones signify non-ferrous targets. With no visual identification available, the designers focused on enhancing the quality of sound identification to improve the user experience.
The volume scale is divided into two sections. For scale units 1 to 5, the volume of the signal received from any target increases proportionally. In contrast, scale units 6 to 10 maintain the same volume for large targets while allowing the volume to grow for smaller and deeper targets. This design ensures that users can effectively identify and differentiate between various targets underwater, enhancing the efficiency of their treasure hunting endeavors.
Ground balance
The Fisher CZ-21 features a manual ground balance function that can be adjusted within a range of 1 to 10. This capability is crucial for optimizing performance in various soil conditions. By adjusting the ground balance, users can effectively search in highly mineralized environments without a significant reduction in detection depth.
This feature is especially beneficial in challenging terrains, such as rocky or sandy areas, where mineralization can interfere with detection. Additionally, the patented Fourier Domain technology ensures the metal detector operates efficiently in brackish sea water, further enhancing its performance for underwater treasure hunting.
Discrimination
The DISC potentiometer on the Fisher CZ-21 is essential for adjusting the discrimination function, which helps users filter out unwanted targets. To tune the discrimination level effectively, set the device to silent mode and turn the potentiometer between 0 and 6. For those who prefer an ‘all metal’ mode with a threshold tone, simply use the AUTOTUNE setting.
It’s important to note that turning off discrimination can enhance detection depth, but this improvement mainly applies to smaller targets. In my experience, I haven’t observed a noticeable increase in detection depth for standard coins or gold rings under these conditions.
The Fisher CZ-21 employs a sequential discrimination function, requiring users to exclude unwanted targets step by step. Start by deactivating the segment for ferrous targets, followed by small non-ferrous targets. This process ensures optimal performance, making the detector most effective when set at the lowest discrimination level.
The discrimination feature is particularly useful in environments where a mix of metals is present, such as beaches or urban areas, where non-target items can easily be detected. By adjusting the discrimination level, users can save time and effort by avoiding unnecessary digging for less valuable targets, allowing them to focus on more promising finds.
Conclusions
The Fisher CZ-21 is a metal detector designed for immediate use, allowing users to embark on treasure hunting right after purchase. Known for its user-friendly interface, the CZ-21 is straightforward to operate, making it accessible even for beginners. Overall, this device stands out with its impressive detection depth, clear sound signals, and robust construction.
One of the CZ-21’s significant advantages is its exceptional performance in brackish water, where it experiences minimal phantom signals. This reliability is crucial for underwater treasure hunters, as it ensures accurate readings. Additionally, the CZ-21 effectively ignores hot rocks and black sand, which can often complicate detection for other metal detectors.
In the competitive market of underwater metal detectors, the Fisher CZ-21’s primary rival is the Minelab Excalibur II. While the Excalibur II is lighter and offers superior sound indication quality, the CZ-21 remains a strong contender, particularly for those seeking durability and ease of use.