Reef Octopus NWB 150 Needle Wheel Protein Skimmer. **** PRODUCT MANUAL **** Popular design that works by a special wheel inside the skimmer pump which chops the air and water into fine micro bubbles. Special needle wheel produces more micro bubbles which highly increases the skimming ability compared to our competitor’s models. Simple to use! Plug it in and set the water level using the telescoping riser tube. Octopus NWB 150 Specifications: - For In-Sump use only - Recommended for tanks up to 150 gallons. Dimensions: - Overall Height: 22 1/8" - Cup Removal Clearance: approx. 1" - Reactor Diameter: 6" - Needle Wheel Pump included (approx. 530 gph) - Footprint (including pump): 12" x 8.5"