Audio Research Reference 250 Monaural Amplifier
Visually understated and sonically breathtaking, the Reference 250 is unmistakably Audio Research.
You can find plenty of reviews on-line so I invite you to read them to see the virtues of such monoblocks.
The condition of the devices are like new, both aesthetically and functionally. If you're looking for them this is a very good opportunity.
With original packaging and manuals.