Google did not find anything useful about this cab. (A search for Ross Systems returns PA Speakers and monitors.) It appears that this cab may have originally had Fane speakers in it (based on the badge on the front), but it had two Eminence Private Jacks in it when I received it.
It appears to be made of plywood (not MDF/particle board), which would help explain why it is about 10-20 lbs lighter than a typical 2x12 cab.
Speakers:
• Two 12” Eminence Private Jacks (based on a Celestion Greenback)
• 50 watts each
• 8 ohms each.
• The speakers are currently wired in series yielding 16 ohms for the cab. (If you change the wiring to parallel with these two speakers you will get 4 ohms.)