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 -Optimal- has an electrical connection of 230 volts 5 watts and the capacity is 250 l/h, cable lenght: 1m. The air performance is adjustable. Measurements: 130x70x50 mm