You can use the Zanussi EFF75 Carbon Filter 2 units to make your range hood suitable for the recirculation setting. Your range hood will no longer send the air outside, but will filter it. Then, the range hood blows clean air back into the kitchen. This means you won't smell anything from your fried fish or last nights frying. There are 2 filters in the package that are suitable for the Zanussi XXX.