The AT33MONO is made specifically for use on mono systems. It has a horizontal coil, and so in principle only generates electricity horizontally.
The AT33MONO produces sound to a very high quality because it does not easily pick up unnecessary strain components from distorted or scratched records, producing audio that you couldn't possibly get from a stereo cartridge.
The AT33MONO also has appropriate compliance in the vertical direction, so will not cause damage to stereo records. Enjoy those well-known classic mono records of yesteryear with the AT33MONO.