With 8" Coil  - Fully Submersible

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• Manufacturer's Limited Warranty

• Made in the USA 🇺🇸

Purpose: Valve & Box Locator

The Fisher M-66 is an all-metal, professional-grade metal detector designed specifically for utility workers, municipal crews, and contractors. Engineered for simplicity and effectiveness, it excels at locating valve boxes, manhole covers, and other buried metallic infrastructure—even through asphalt and concrete. A standout feature is its double-D search loop, offering stable performance and deeper detection.

Operating at 4.5 kHz, the M-66 provides consistent and accurate detection of ferrous and non-ferrous metals. Its analog meter and audio tone alert users to changes in signal strength, ensuring quick identification of buried targets. The detector uses manual tuning and ground balancing to adapt to varying soil mineralization, while the threshold-based Tuning Control allows users to optimize sensitivity. The search loop is immersible, supporting work in wet environments.

Built for demanding field conditions, the M-66 features a rugged frame with an adjustable shaft (28"–48") and an 8" waterproof coil. Weighing just 4.25 lbs, it offers comfortable handling over long shifts. Powered by dual 9V batteries, it delivers extended operation and includes a battery test function to prevent downtime. The control layout is intuitive, making it easy to train new users and ensure reliable performance in daily operations.

Specifications

• Manufacturer: First Texas Products, LLC
• Brand Name: Fisher Research Labs
• Country of Origin: USA
• Warranty: 2 Years
• Output Frequency: 4.5 kHz
• Audio Output: 450 Hz via 16-ohm speaker
• Power Supply: 2 x 9V batteries
• Power Consumption: (-9V) 17 mA; (+9V) 4 mA min, 6 mA sound threshold, 125 mA max sound
• Weight (with 8” coil): 4.25 lbs (1.93 kg)
• Operating Temperature: -4°F to 158°F (-20°C to 70°C)
• Search Coil: 8" fully submersible
• Adjustable Shaft Length: 28" to 48" (71 cm to 122 cm)
• Shipping Weight: 7 lbs (3.18 kg)
• Shipping Dimensions: 34.75" x 12.75" x 5.25" (88.3 cm x 32.4 cm x 13.3 cm)
• Target Indication: Analog meter and audio tone
• Tuning & Ground Control: Manual threshold and ground rejection controls
• Metal Detection Type: Detects all metals including aluminum, brass, copper, iron, nickel, steel, and tin
• Design Features: Weather resistant, built-in battery test, simple 2-knob operation