Reef Octopus Classic 1000-HOB Protein SkimmerHang On Back Protein Skimmer Rated for up to 130 Gallons Footprint: 8. 8" 3. 5" Height: 17"Pump: Reef Octopus Aquatrance 1000s Ultra Slim Hang On Back Skimmer The compact Reef Octopus Classic 1000 HOB is a proverbial favorite amongst hang on back protein skimmer users providing beneficial filtration for aquariums up to 130 gallons. With its unique design, the pump is mounted externally and under the actual skimmer body allowing for much less room