Fisher M-66 Metal Detector

Fisher M-66 Valve and Box Locator Metal Detector

Purpose built for locating buried or paved over valves, boxes, manhole covers, and other concealed metallic objects across utility sites.

The M-66 is designed for utility and construction professionals who need an all-metal detector that combines rugged reliability with straightforward operation. It is well suited for field crews working in varied conditions, from soft soils to paved surfaces, where infrastructure is hidden beneath layers of dirt, asphalt, or concrete. Its balance of precision and durability ensures that operators can locate key access points quickly and accurately, minimizing excavation errors and downtime.

Core Features and Operation

The M-66 is engineered for efficiency in real-world utility workflows. Rather than complicating the process with unnecessary features, it provides straightforward controls that allow operators to focus on detection and marking. The instrument offers responsive tuning, stable audio, and clear visual readouts, making it particularly effective in fast-paced environments where time and accuracy are equally important.

• Simple two knob control for power, sensitivity tuning, and ground rejection
• Built in battery test for quick readiness checks before deployment
• Analog meter and audible tone for immediate user feedback
• Ground rejection VLF (Very Low Frequency) circuit reduces false signals from mineralized ground
• Adjustable shaft for ergonomic positioning during extended sweeps

Detection Capability and Construction

The M-66 has been built to withstand demanding field conditions, making it an indispensable tool for locating metallic infrastructure. It is capable of detecting all common metals and provides strong penetration through challenging surfaces such as compacted soil or asphalt. Its waterproof coil extends functionality to wet environments, and its weather resistant housing ensures long service life even with daily outdoor use. This combination of sensitivity and durability makes the M-66 highly reliable for utility work where conditions are rarely ideal.

• Detects all metals including aluminum, brass, copper, iron, nickel, steel, and tin
• Sensitive performance with deep penetration through soil, asphalt, or concrete
• Fully submersible 8 inch waterproof search coil for wet or flooded conditions
• Weather resistant housing that protects electronics from dust and moisture

Technical Specifications and Ergonomics

The M-66 delivers a strong mix of performance and user comfort. Its lightweight build and adjustable length allow it to be tailored to different operator heights, reducing strain during prolonged surveys. With its dependable battery life and broad operating temperature range, it is designed to handle both short-term tasks and all-day operations in demanding conditions. By offering precise detection depths, the M-66 provides confidence that valve boxes, manholes, and other targets will be located without unnecessary excavation.

• Frequency: 4.5 kHz, suitable for a variety of metal targets
• Weight: Approximately 4.25 lb (1.9 kg) including coil
• Adjustable length: 28 in collapsed to 48 in extended (71 cm to 122 cm)
• Battery: Operates on two 9V batteries with typical life from 15 to 25 hours depending on conditions
• Operating temperature range: –4°F to +120°F for year-round use
• Detection depths: Valve boxes up to 18 in deep and manhole covers up to 42 in deep
• Warranty: Two year limited

Why Field Operators Choose the M-66

The M-66 is trusted by utility crews for its balance of simplicity, accuracy, and ruggedness. It requires minimal training, performs reliably across a variety of terrains, and reduces the risk of costly mistakes during excavation. Operators choose it because it provides confidence in the field, ensuring that buried infrastructure is quickly and accurately located. Its combination of proven design, consistent depth performance, and portability makes it one of the most dependable valve and box locators available.

Contact Green Equipment Company to request pricing or arrange a demonstration of the Fisher M-66.