ERI Fill Extensometer

The ERI is a telescopic extensometer used to measure longitudinal displacements and axial deformations over long base lengths.


The fill extensometer Model ERI consists of a telescopic outer PVC pipe fitted with two end flanges and an inner stainless steel rod. One end of the rod is attached to a flange, while the other end of the rod is attached to a displacement sensor, which is attached to the other flange. A signal cable attached to the sensor links the sensor to a readout at the surface. As displacement occurs, the telescoping outer pipe moves with the soil, causing the rod to compress or extend the displacement sensor.

These fill extensometers are generally installed horizontally in trenches, but sometimes vertically in boreholes. The standard lengths of the fill extensometer Model ERI are between 3 meters and 6 meters. Extensometers can be assembled in series using threaded rods inserted in the holes on each.

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Available Products

ERI Fill Extensometer
[ERI Fill Extensometer]
Please contact for pricing


Product Details



25, 100, 150, 200 and 300 mm

Sensor type 

Vibrating wire


±0.25% F.S. 


0.02% F.S. (MB-3TL)


 IRC-41A(P), IRC-390

Thermistor (optional) 


Operating temperature 

−20 to +80°C

Base length 

3m (longer upon request)

Outside diameter


Stainless steel extension rod 

6.35 mm

End flange 

150 mm

PVC telescoping coupling 

42 mm

PVC sensor housing 

48 mm 

PVC casing 

33 mm

Readout unit 


Data acquisition system 



    Please specify:

  • Base length and range
  • Electrical cable length

    Optional accessories:

  • 1m rod and tube Readout instruments
  • Readout instruments