The PCH 4051 Vibration Checker includes a separate accelerometer with a strong magnet for measurements on hard-to-reach machine parts. You can measure the vibration level in 3 units; velocity, acceleration and in displacement. The PCH 4051 complies with the DIN/ISO 10816 standard. Furthermore, the PCH 4051 measures bearing noise in the 1 kHz - 10 kHz area. If you use a magnet, or a threaded stud, for positioning the accelerometer you get a more repeatable measuring results. This is very recommendable when you make several measurements and want to compare the data over time.