This package includes two 'matched ASC EQs', along with a rack mounting assembly...and it all works off one "wall wart" power supply. The main difference between the ASC and the ASC-T is that the ASC-T has the choice of a transformer or transformerless output where with the ASC you only have transformerless output. There is a distinct sonic difference between going through the transformer and going transformerless... with the ASC-T you get the choice of two sonic output differences.