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Magnetic Extensometers | Model 1900

  • Model 1900-11 Reed-Switch Probe and Index Marker.
  • Model 1900-11, Index Mark closeup.
  • Model 1900-5A (left) and Model 1900-5B (right) Datum Ring Magnets.
  • Model 1900-7A Anchor, shown before and after release, for use with 1" access tube.
  • Model 1900-7B Anchor, shown before and after release, for use with Model 6600 Inclinometer Casing.
  • Model 1900-6A Plate Magnet, for use with 1" access tube.
Model 1900

The Model 1900 Magnetic Extensometer is designed to measure settlement or heave of soft ground under the influence of loading or unloading due to the construction of embankments, fills, buildings, foundations, and structures. A probe is lowered inside a telescoping guide tube to detect and measure the position of magnetic anchors located around the guide tube at various depths along the borehole or within the fill. Plate anchors are used in fill and “spider” anchors in boreholes.


Cable Lengths
30, 50, 100, 150, 200 m; 100, 125, 200, 300 ft
1 mm
±3 mm
Temperature Range
−30°C to +80°C
Borehole Size
102 to 216 mm
Probe Dimensions (L × Ø)
178 × 19 mm

Please Note: GEOKON maintains an ongoing policy of design review and reserves the right to amend products and specifications without notice. Various instruments are discontinued over time and replaced with new, updated models.