Sweetwater SL22 Linear Air Pump. **** Sweetwater Linear Pumps - Flow Curves **** These are not linear "diaphragm," but true linear "piston" type pumps. Since the only moving part - the piston - floats on a bed of air, an exceptionally long service life can be expected (8 years of continuous life is not uncommon). You get quiet, energy-efficient operation and clean, oil-free air. An outdoor-rated housing, grounded power cord, 1/2" MNPT flex outlet and 115V/60 Hz are all standard. UL-listed. 1-year warranty. SL-22 Specifications: * 81" max depth* Dimensioons: 7" x 7" x 8" * Power Consumption: 48 running watts * Output: 1.8 cfm of output at 2 psi.