What is the frequency response of the unit?

Actually, for many measurements I prefer an appropriate analog meter.

At one point, in cooperation with a manufacturer, we held a "clinic". The national service manager came to town to participate. Early in the day he criticized me for not providing a DVM for the low level measurements. After he got to know the instrument, he admitted to liking my "old fashioned" analog meter. (1mv full scale, this was not a cheap meter)

Yes, you can easily find a digital meter with four or five digits, but two or three of the digits are usually bumbling around, forcing one to mentally average the bumbling. An analog meter will automatically smooth over a little noise.