Are you talking about the box that is linked on DAs site?? If so, it should give you the dimensions and cutsheets. At least it did the last time I visited their site.
If you are talking about that one, all the cut sheet dimensions are on there. For net volume, just take the outer dimensions, subtract 1.5" from each value and multiply. Then calculate the volume of the ports with the dims listed and subtract them from the total volume.