The main advantage of the Vibrating Wire Inline Extensometer is that it has no electrical head protruding from the borehole, unlike conventional Multi‑Point Borehole Extensometers (MPBXs). The Inline Extensometer sits flush with the borehole collar or ground surface and measures movement at multiple depths relative to a designated reference point.
All displacement transducers are housed within sealed head/anchor assemblies installed in the borehole. These assemblies are separated by extension kits of varying lengths, depending on the required measurement depths. The extension sections use rigid 3/8‑inch (9.5 mm) stainless steel rods protected by a 1/2‑inch (12.7 mm) SCH40 PVC sheath. The larger rod diameter—compared with the 1/4‑inch (6.35 mm) rods commonly used in conventional MPBXs—provides increased accuracy for both extension and compression movements.
As all displacement transducers are installed in series, the total measurement range of the extensometer equals the sum of the individual transducer ranges. This allows the system to measure significantly larger movements than conventional MPBXs while using lower‑cost, standard‑range transducers.

Product features:

• Flush with surface: no electrical head protruding out of borehole
• Can be used as a single or multi-point measurement system
• Suitable for small and large extension and compression movements
• Can be installed in smaller boreholes compared with conventional MPBX
• Rigid 3/8 inch (9.5 mm) inner stainless steel rod provides more accurate displacement measurement.