Model M-66 Valve and Box Locator by Fisher

8" Coil. Locates Buried or Paved-over valves, Boxes, Vaults or Other Metal Objects


Fisher's M-66 Valve and Box Locator is designed specially for finding buried or paved over valves, boxes or vaults. In addition, the M-66 locates survey markers, water or gas meters, conduit, manholes and any other concealed metallic objects. The M-66 detects all metals including aluminum, brass, copper, iron, nickel, steel or tin.

Combining sensitivity and accuracy with maximum ground penetration, the M-66 eliminates any guesswork when pinpointing hidden metallic objects. The electronic balance of the M-66 is easily and quickly tuned for detection within seconds, while also allowing for maximum audio and visual indications.

In the Fisher tradition, the M-66 is affordable, tough, and simple to use while providing maximum performance. A two-year limited war­ranty comes standard with the unit.



  • Simple operation - only 2 knobs.
  • UItra-sensitivity and maximum penetration through soil, asphalt or concrete.
  • Ground rejection VLF (very low frequency) eliminates false signals.
  • Detects all metals.
  • Built-in battery test.
  • Analog meter and audio target signal.
  • Adjustable shaft.
  • Fully submersible 8-inch search coil.
  • Weather resistant design.


2-Year Warranty

Fisher warrants the M-66 to be free of defects in material and workmanship when it is shipped from the factory. The terms of this warranty are fully explained in a warranty registration card that accompanies the instrument. Complete factory and field service facilities support the warranty. Warranty may vary outside the U.S. Please see Corrosion Control Products Company for details.

M-66 Specifications

  • Search Loop Configuration:
    Double D (direct wired)
  • Loop Output Frequency: 4.5 kHz
  • Output Indication:
    Speaker: 16 ohm impedance
    Audio frequency: 450 Hz
  • Power Supply: 9V, each
  • Power Consumption:
    (-9V): 17 mA
    (+9V): 4 mA min, 6 mA sound threshold, 125 mA max sound
  • Weight: 4.25 lbs with 8" coil
  • Operating Temperature: 
    -4°F to +158°F (-20°C to +70°C)
    Search loop immersible in water
  • Dimensions:
    Length 28" to 48" (71 cm to 122 cm), adjustable
  • Shipping Weight: 7 lbs
  • Shipping Dimensions: 
    34.75” x 12.75" x 5.25" (88.3 x 32.4 x 13.3cm)