21 ELECTRICAL APPARATUS-NAMELY, TRANSDUCERS, DETECTORS, AMPLIFIERS, INTEGRATORS, OSCILLATORS, SOLID STATE CIRCUITS, CABLES, STROBOSCOPE LIGHT DEVICES, AND COMPONENTS THEREFOR
26 APPARATUS FOR OBSERVING AND MEASURING MECHANICAL VIBRATION INCLUDING SUPPORT STANDS; VIBRATION PICK UP DEVICES; DEVICES FOR METERING, INDICATING, AND RECORDING MECHANICAL VIBRATIONS
VIBRATION INVESTIGATION AND MEASUREMENT SERVICES FOR CONTINUOUS AND PERIODIC MONITORING OF UNBALANCE IN ROTATING BODIES AND FOR CORRECTION OF SUCH UNBALANCE