Gauge models: Impact TH-130™ Standard model with integrated impact device D Impact TH-132™ Special model for Hardness Measurement on surface hardened components, coatings, thin walled components. It has app. 1/4 impact energy of Impact TH-130/134™. Integrated impact device C. Impact TH-134™ Special model for Hardness Measurement in extremely confined spaces. Integrated impact device DL. The Impact™ is a handy portable hardness tester with an integrated impact device. It can be used in any position, even upside down. Readings can be printed out immediately on a mini-printer or stored for later processing.