I was recently given a MA Cotter Co. Moving Coil Pickup Transformer Mk2L. That's all it says on it. Accept for the Serial number on the bottom. Does anyone know anything about this unit? How to use it? How much it is worth? I know absolutely nothing about step-up transformers. Any help would be appreciated. Oh the unit also has on it what looks like a Clearaudio logo.

Thanks in advance.