Stethoscopes for locating noises within machines and installations, such as those made by ventilators, pistons or pumas. These stethoscopes are ideal in preventative maintenance to check noises, control of vibrations, or the oscillation of pieces within the research and development sectors of for continuous inspection. Noises made by moving components are significantly amplified with the help of a stethoscope and environmental noise is reduced by way of the well insulated headset. Electronic Stethoscopes are delivered with two different measurement points, which allows for measurements in places that are difficult to access. Some stethoscopes models offer additional functions, such as the Fourier analysis (FFT) for the accurate diagnosis of oscillations in the industrial sector, another additional function is the simultaneous detection of revolutions, or the optical inspection of the equilibrium mismatch.