Neff Z51INT0X0 Recirculation Kit is a premium solution for efficient and effective recirculation operation. This advanced kit comes with an active carbon filter and a stainless steel grille for fitting. It will create a fresher and healthier kitchen environment for your family. This efficient filter recirculates the air to keep bad food odours at bay by absorbing the grease residue left behind after use. We recommend that you replace your carbon filter at least once every 6 months for optimum efficiency.