Bench top LCR meters often have a variable test voltage, so it makes sense when writing a specification to specify it as well as the test frequency to get repeatable results. The small difference between 1 V rms and the DE-5000 with a fixed value, approximately 0.6 to 0.7 V rms (my measurement, I’m not sure DER states it), should not be important, but the frequency is important. I concur with graybeard’s recommendation of the DE-5000.