The Faber DUCTCLAS Ductless Conversion Kit is used for installations where ductwork is impossible or impractical. Every Faber chimney wall style and island range hood except for the Fortezza Isola, has the ability to be converted to ductless. It is highly recommended that professional style cooking always be vented to the outside. The Classica ductless conversion kit consists of: thick, high quality charcoal filters to absorb odors, and a ductless diverter piece to channel air back through the vent holes in the sides of the chimney. The Classica, Gemma and Glassy range hoods all come with a ductless chimney out of the box which makes converting these hoods to ductless more affordable.