Its jeepguys 2-18 kerfed box with a 50lb dog in a 18 ft^3 box. I was joking with him yesterday about the size decided to get the dog to pose for a pic for scale funny thing is she really got comfortable and didnt want to come out.
Its actually ends up being 12 cubes after all the interior displacements. The shoulders also make it appear bigger but we needed the extra width for the 18's and their mounting rings.