This chapter considers appropriate HopkinsonHopkinson bar instrumentation. By far the most important is the use of surface mounted strain gaugesGauge – strain to measure the stress wavesStress wave in the input and output barsOutput bar, and a section is devoted to these. Other methods for instrumenting the bars and bar-specimen interfaces are the considered, before moving on to optical methods for measuring the strain in the specimen. Finally, the use of thermal and X-ray imagingX-ray imaging techniques is discussed. Much of the information on strain gaugesGauge – strain and electric circuits is available in standard textbooks, which are not referenced here. A good reference for semiconductor GaugesGauge – semiconductor is the Kulite Strain Gage Manual ( https://kulite.com//assets/media/2021/11/StrainGageManualDigital.pdf last accessed on 2024 04 24), which also contains information about conditioning for foil gauges.