Cad Lights PLS-300 Pipeless Protein Skimmer for Aquariums, 420-Gallon A patent pending Pipeless design; professional air injection; bubble plate; pin-wheel impeller and a locking system to hold the skimmer level settings Compact and space-saving with a foot print of just 9" x 11" For aquariums 300 gallons to 400 gallons Full interlocking gear control system and built-in baffles that returns the water with zero micro bubbles discharge Dimensions: 11" x 9" x 28"