The BEAST DEFENDER by Winflex is very convenient and offers a premium protection against insects while having a good air circulation. The plastic mesh BEST DEFENDER is to place easily on or outside the extractors and pipes. Elastic, this filter is to put with Velcro bands for a better hang. It catches insects and mold. You can use it on extractors and introducers. For introducers of culture room, you will have to add a metallic duct according to right diameter. Resists UV and it is washable.