The Metabo operates its speeds in the way of numbers much like the PC. Starting at 1, being I believe 700 rpm's, up to 6 which I believe is 2000 rpm's.
I could have those wrong as I have not read up on it since I bought the Metabo some years ago.
The Metabo PE 12-175 has variable speed settings from 700 rpm to 2200 rpm, which can be preset via the thumb-wheel. The speeds correspond to the settings as follows: