This Bundle has THREE items: the Reef Octopus OCTO Classic 100-HOB Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 105 gallons, light bio load; 75 gallons, medium bio load; and 55 gallons, heavy bio load. The Reef Octopus OCTO Classic 100-HOB Protein Skimmer is a favorite hang-on back skimmer. Capable of filtering aquariums up to 105 gallons, the Classic 100-HOB features an easy to install and operate design in which the pump is mounted inside the aquarium. Footprint: 8in x 3.25in. Total Height: 17in. Pump Information. Reef Octopus Aquatrance 1000s Pinwheel Pump. Wattage: 9w. Air Draw: 420 lph / 15 SCFH. Water Draw: 350 lph / 92 GPH. Features: Adjustable Surface Skimmer; Reef Octopus Aquatrance 1000s Skimmer Pump; Low Profile body; Air Silencer; Solid Acrylic Construction; and Efficient Performance. 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 100-HOB Protein Skimmer; a FREE MarineAndReef Reefractometer; & a Towel. For aquariums up to: 105 gallons, light bio load; 75 gallons, medium bio load; and 55 gallons, heavy bio load.