An extensometer is a device that is used to measure small/big changes in the length of an object. It is useful for stress-strain measurements.

These extensometers are mainly split into two categories

  • Non Contact
  • Contact

Non Contact Extensometers:

Video Extensometer
For certain special applications, non contact extensometers are used for its added advantages especially where it is impractical to use a High Elongation or a Clip-On Extensometer namely the Video Extensometer.
The up-to-the-minute Dak Advanced Video Extensometer (AVE) is a high performance non-contact extensometer with measurement performance that meets or exceeds that of traditional contact extensometers. High performance is matched by an ergonomic LCD color touch screen design in conjunction with Image Dimensioning Software (iDs) that allows easy set-up and provides very good operator access to the test area.

Contact Extensometers:

Contact extensometers can be subdivided into two further categories:

Clip-on Extensometer These are clipped onto a specimen (hence the name “clip-on” extensometer) before carrying out a tensile test. These devices are used for applications where extremely high precision is required over a relatively small extension (a few mm).

High Elongation Extensometer


Designed for measurement of higher extensions on plastics, rubbers, elastomers, cellular plastics, thin sheeting and films showing maximum forces higher than approximately 20 N. The special design of the gripper arms of the extensometer releases the specimen at break especially for testing of rubbers and elastomers showing a tendency to wrap around the sensor arms at failure.


– Gauge length adjustable from 15 mm to 50 mm

– Travel range 800 mm

– Resolution 0.01mm(10 microns)

– Suitable for Elastomeric materials like polymers, rubbers, plastics, etc