Polytec laser vibrometer with OFV-2500 controller and OFV-503 sensor head is designed to measure velocity of vibrations in the range of infrasonic, audible and ultrasonic frequencies. Vibrometer allows measurement of velocity in the range of 10, 100 and 1000 mm / s / V and can be used to measure the velocity and displacement of diaphragm, to diagnose vibration of mechanical components, identification of noise sources, etc.