Penguin Power Filters deliver constant flow with fully adjustable aeration and increased surface agitation, and they remain silent at all times. The custom air valve regulates air flow, the air filter eliminates noise and dust, and the intake strainer keeps debris from fouling the impeller. Safe for both fresh and salt water applications. UL and CSA listed. Epoxy sealed, moisture-proof motor and electrical components ensure safe operation. Unique mounting system adjusts to any demand. Adjustable flow diffuser and aeration valve deliver ideal surface agitation and maximum oxygenation. Certified accurate flow rate.