A special feature of this hob extractor is its use of a maintenance-free berbel permalyt recirculation filter. Their filter mats consist of a special activated carbon that absorbs odorous substances during normal operation and in the process binds up to 97 per cent of these odours. The regeneration process in the closed filter system starts after 30 minutes of continuous cooking or 60 minutes in total. A thermal catalysis process neutralises the odours with the help of a catalyst.