The most popular washable type filter on the market is this expanded aluminum mesh filter. It is used as an HVAC air filter as well as a grease filter in residential range hoods. This filter is produced by building up various layers of expanded aluminum materials bonded together to form the filter pad. These bonded layers form a baffle effect to trap airborne contaminates. Filter is available in standard and non-standard sizes, and in thickness' of 1/8", 3/8", 1/2", 1" and 2"