Those are US 100 HC's...They use the same board as the US 2000x only difference is they produce 2000+ at 1 ohm instead of 4 like the 2000x....There were only 4 like mine built before US Amps changed hands...one was destroyed by 17volts....I have no idea where the other is It was originally sold to some famous ball player...I have all the boxes...manuals...and badges were never mounted...they are clean except for some finger prints on the casing.....
or you can just call your friend that sells us amps and ask him //content.invisioncic.com/y282845/emoticons/rolleyes.gif.c1fef805e9d1464d377451cd5bc18bfb.gif