Oxygen is vitally necessary for fish and primitive sea species in the aquarium, for they have no CO2-respiration. Leading experts also recommend oxygen as remedy for the regen-eration of diseased fish. A airation pump is also useful for the operation of internal air driven filters, protein skimmers or decoration figures. All Schego membrane pumps work extremely reliably in continuous operation and are characterized by very quiet running, they have little vibration and are stable. The model SCHEGO -M2K3 WS3- has an electrical connection of 230 volts 5 watts with an output of 350 l/h and comes with an increased output pressure of 0.3 bar for the operation of protein skimmers, deko water column, cable lenght: 1m. The air performance is adjustable. Measurements: 170x75x60 mm