[eventhorizon]

This is a factory-built amp and is in 9/10 condition.  Used for very few hours... This is one of those amps that far exceeds its price point. 

More info can be found here. 

http://classdaudio.com/audio-amplifiers/sds-250c-class-d-audio-power-amplifier.html

Details about the amp module and specs here.

http://classdaudio.com/amplifier-modules/sds-254-amplifier.html

Asking $425 plus shipping.

These rarely come up for sale used, and its with good reason.  Won't find a better deal than this in terms of pure amplification.

[poseidonsvoice]

Great amp, and underrated! Shouldn't have sold mine! Good luck with your sale 

Anand.