This filter contains a microfilter and an activated carbon filter. The limescale filter reduces the hardness of drinking water by removing limescale. The filter is also designed to prevent corrosion in the boiler. Furthermore, it removes impurities, odors, and unpleasant tastes (such as chlorine) from the water, improving its taste. The capacity of this filter is approximately 2100 liters. The filter should be replaced at least once a year. In areas where the water hardness is above 10°C (10°F), the use of a filter is recommended. A filter is not required for titanium boilers.