Proceq Schmidt ® concrete testers are used for the non-destructive measurement of the concrete/mortar compressive strength and the control of the uniform concrete quality (in-situ concrete and prefabricated structures) as well as for detecting weak spots. The compressive strength (fc) is established by measuring the hardness (rebound value R) of the concrete surface and with the conversion curves. ORIGINAL SCHMIDT ® Concrete test hammers with various impact energies can be used depending on the form and sizes of the concrete structures (lower impact energy for thin and/or weak components).