Measurements taken with the Hioki 3280-10F (which uses the mean value method) and the the Hioki 3280-20F (which uses the true RMS method) are compared. Observe the difference between readings from these two types of instruments when measuring a distorted waveform that contains harmonic components such as those produced by inverters and switching power supplies., When connected to an optional flexible current sensor, the 3280-10F can be used to measure the current flowing in pairs of wires or in tangled or complexly routed wires around which it was not possible to apply a clamp-on sensor in the past., The 3280-10F delivers all the functionality of a clamp meter and card tester in the form factor of the latter. In addition to current measurement, this single instrument delivers voltage measurement, continuity check, and resistance measurement functionality.