Description Hakko pumps are high volume diaphragm pumps designed for a variety of low-pressure applications. Koi pond aeration, large aquarium aeration and earth pond destratification are only a few of the many applications for Hakko pumps. Hakko pumps are compact, affordable,  energy-efficient, and very, very quiet (less than 28 decibels)! Hakko units utilize   linear-motor  theorem to reduce power consumption during full operation. Units are extremely quiet  utilizing spectrum analysis technology in order to decrease any mechanical noise. No oil needed for lubrication making the Hakko easy to maintain These are the best air pumps available today 18 month warranty through the manufacturer Maximum Airflow: 65 lpm/2.3 cfm Maximum Depth: 14 1/2 Watts: 40 Case Count: 4 (Sold Individually)