The main reason I bought this model over others is that it has a frequency measurement function in Hz. I tried using this to test the frequency stability of my oscillator and got a reading of minus 2.51-2.58kHz. When I measured a standard outlet, I got the same numbers. Of course, the number I was expecting was 60 Hz. If the meter has a Hz measurement capability, it must be able to read at least the US standard voltage frequency of 60 Hz. All other features, which are admittedly much more important, work well.