Used to perform freeze-thaw tests, dynamic testing of concrete specimens, assess uniformity of in-place concrete and evaluate expansion, bending and twisting of wood, metal, plastic, ceramic and other materials by measuring changes in resonant frequency. The unit consists of a 30 W portable driver, pick-up circuit with a cartridge mounted on an adjustable metal stand and control unit with 3 in (76.2 mm) oscilloscope, voltmeter, counter and amplifier. Amplitude and frequency of vibrations can be controlled in ranges of 0 W to 25 W, 400 cps to 12,000 cps, frequency displayed to ±2%. Counter displays to ± one digit. Overall box dimensions: 17 in x 14 in x 11 in (43.2 x 35.6 x 27.9) cm.