The Air Handler 3-Ply Panel filter incorporates three distinct filter layers. The first layer acts as a high-porosity impingement filter and the second as a durable strainer to prevent unloading or streaming. A non-migrating tackifier between the two layers laminates assures positive filter-cake build up. This filter achieves a high level of efficiency on a wide range of particle sizes. The 3-Ply filter is an ideal filter for medium efficiency applications. Panels offer approximately three times the life of fiberglass dosposable filters. When used as pre-filters, these filters will add substantially to the life of more expensive high efficiency filters.