Built for exceptional performance, permanent metal filters have a large dust-holding capacity. Multiple layers of pleated metal, aluminum, galvanized, or stainless steel capture more dirt, and lightweight construction makes these filters easy to handle, install, and clean. Permanent metal filters are used for general air filtration in any HVAC system as well as prefilters to higher efficiency filters. They are especially suited for applications requiring permanent, washable or high temperature filters with rust resistance.