here is some information about these types of air filter
This is NOT a foam-core filter. The washable type industrial grade filter is built to withstand frequent and moderate cleanings. An aluminum frame Eco-Aire filter is the lightest weight filter in the industrial grade class. It is designed for use in commercial and industrial applications to filter air, grease and coolant mists, and it can be used either dry or coated with filter adhesive.
Uses: To be used in ceiling fans, central air conditioners, electronic equipment, ventilating windows, heating equipment, kitchen air exhaust and recirculating systems, range hood fans, wall heaters, and ventilation openings that require protection.
Doubles as an Attenuator: For sensitive electronic equipment, the filters can provide protection from electromagnetic and radio frequency interference as well as from airborne contaminants. The filtering media doubles as an EMI/RFI attenuator and air cleaner.
This washable filter uses a .030" thick 3003 H-14 aluminum frame to enclose the filter media pack. The corners are mitered and theframe is secured with pop rivets. The media consists of multiple layers of corrugated aluminum baffles, bonded in a criss-cross fashion for strength, placed between two expanded galvanized steel grids. The media is made to fit firmly inside the frame giving the washable industrial grade filter its exceptional strength and durability. Maximum temperature: 225 degrees F.