The aquarium heater is available in four sizes: thermopreset 50, thermopreset 100, thermopreset 150 and thermopreset 200. The slim design with a diameter of only 2,8 cm applies to all four sizes.Diameter: 28.2mmMax temp: 25 degreesPerformance at 50 Hz: 200 WattFor aquariums of about.: 300LFor aquari..