This SWR SM-400 is one of the rack mount bass amplifier heads the company made in the 90's. It has an all-tube pre-amp section fitted with 12AX7's, and two solid state power amps for the ability to run the amplifier as a bi-amp configuration. It can run at 400 watts at 8 ohms, and 440 watts at 4 ohms.

This amplifier is in very good condition with some small scratches on its faceplace. The rack case that was included with it shows signs of wear but is structurally intact.