I think what you have is a UL 710 appliance, which is a stand alone unit. They are 220V, with a 2.5 # Ansul FX filled w/Ansulex chemical. They have 1 or 2 links, nozzels, nozzles caps and a remote pull station. They are to be serviced twice a year.
There is no hood, duct, or separate fan required. You should be able to go the web-site for more information.
Auto Fry is one of several mfg of these units. All of them need an initial service as they are shipped w/o being armed. Some, specifically Giles, may or may not have the cartridge, agent tank and agent. The most common suppression system is Ansul, but I have also seen Amerex and Pyro Chem brands.