Reef Octopus Classic 2000-HOB Protein SkimmerHang On Back Skimmer Rated for up to 200 Gallons Footprint: 10" x 4" Height: 21" Pump: Reef Octopus Aquatrance 2000s Ultra Slim Hang On Back Skimmer The Reef Octopus Classic 2000 HOB is a unique design hang on back protein skimmer for marine aquariums that has the pump mounted outside the aquarium and external to the skimmer body allowing for much less room needed behind the aquarium. Also, by placing the pump outside the skimmer and the aquarium, no