A digital tape extensometer is commonly used to measure changes in distance between two reference points in any direction, typically in tunnels, shafts, linings, and caves. It consists of a perforated steel measuring tape wound around a roller fixed to the device’s body.
To accurately read the change between the two reference points, it features a digital LCD. It comes with two hooks, one at the movable end of the tape and the other on the roller frame. For accurate measurement, it is tensioned between two steel rings fixed with screws, serving as the two reference points.
A verification frame can be used regularly to check the repeatability of the device.