The Faber FILTER4 Charcoal Air Filter is compatible with the Inca Smart hood. For any hood that is installed directly underneath or inside of a wood hood or cabinet, charcoal filters only are used to recirculate the hood. A set of 2 filters is the only part that comes in a recirculating kit. Hoods that are recirculating (except the Matrix and Mirror), require a small amount of ductwork to divert the air to the top of the cabinet or the face or side of the soffit. However, the ductwork does not have to exit the home, but rather return the air back into the kitchen. Click here to see a picture of a hood with a recirculating installation.