Good Filter Company standard duty 3/32″, 1/8″, 1/4″, 5/16″ and 3/8″ thick metal mesh air filters are constructed of an inner media pack of of multi-layered expanded aluminum bonded together to make a single filter pad. The layers are expanded at different size openings with the larger openings at the air intake side and becoming progressively smaller through the filter. This makes this filter more efficient than individual layers not bonded together. In the standard duty model, we add a layer of heavy duty expanded aluminum on the exhaust side of the filter for added strength and durability. An air flow direction label is attached to the filter frame for clarification. This filter is then enclosed in a heavy duty aluminum frame and comes in sizes up to 2000 square inches. No one else makes an aluminum metal mesh filter like this.