This Bundle has THREE items: the Reef Octopus OCTO Classic 1000 HOB Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 130 gallons, light bio load; 50 gallons, medium bio load; and 60 gallons, heavy bio load. The Reef Octopus Classic BH-1000 Protein Skimmer is a favorite hang-on back skimmer. Capable of filtering aquariums from 78 to 130 gallons, the Classic BH-1000 features an easy to install and operate design in which the pump is mounted outside the aquarium. Footprint: 8.8in x 3.5in. Total Height: 17in. Reef Octopus Aquatrance 1000s Pinwheel Pump. Wattage: 9w. Air Draw: 420lph / 15SCFH. Water Draw: 350lph / 92GPH. Features: Low Profile Body, Reef Octopus Aquatrance 1000s Skimmer Pump, Efficient Low Heat Performance, Pump Mounted Externally, Surface Skimmer, Air Silencer, and Solid Acrylic Construction. The MarineAndReef Reefractometer is designed specifically for marine and aquarium salt water. The readout is for 0-40 PPT, which is much easier to read than the 1-100 PPT that comes with many refractometers that are for general use. The MarineAndReef Aquarium Cleaning Towel is a durable, lint-free microfiber towel. 19" X 15". This Bundle has THREE items: the Reef Octopus OCTO Classic 1000 HOB Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 130 gallons, light bio load; 50 gallons, medium bio load; and 60 gallons, heavy bio load.