ISO 6892-1
According to type and material of the wire, the gripping mode is different
In case of ductile materials, shaped grips can be used, vice versa wedge grips with fine toothed inserts in case of high resistance wires. We recommend Micron or Micron Motor extensometers, or for particularly thin (hairline) wires the Video extensometer. The latter completely eliminates problems of inertia (drag force) typical of contact (also motorized) strain gauges and extensometer knives engravings on the wire. The gauge length is adjustable at operator's choice and obviously also at 100 mm according to the Standards