This is a very good to excellent A-Designs EM-PEQ 500 series EQ module. It works great and sounds fantastic. It has some marks around the bottom mounting hole as can be seen in the images. This is a great eq unit in a small package.
Make sure your 500 series rack supports this module. It requires 48V to power, the Radial Workhorse Cube allows you to turn that 48V off, it won't work with that rack. It works great with my Cranborne 500 series interface. Signature required