Bison

M/S mid side matrix and dry/wet blender

The IGS Bison 500 is a simple mid/side processor with a dry/wet mixer. It can be plugged into any 500 series rack equipped with a standard power supply. It has two stereo jack connectors (2 sends and 2 returns) on the front panel of the device used for plugging in one dual mono or two mono processors.

http://www.igsaudio.com/bison500