The Helios Fans KWL-WF is a water filter cartridge designed for use in the fresh water supply line of the HygroBox KWL HB humidification unit. This single filter cartridge helps maintain water purity by removing particulates and contaminants, thereby protecting the internal components of the system and ensuring hygienic operation. Please note that the cartridge is supplied without casing or connection hoses. Regular replacement is recommended for optimal performance.