The TRI-DIM TRI-DEK 15/40 is a fantastic alternative to typical pleated media filters and is popular in both residential and commercial applications. If you are in the market for a filter that provides higher filtration performance and requires less frequent replacement, the TRI-DIM TRI-DEK 15/40 3-ply panel filter is a great choice.The TRI-DIM TRI-DEK 15/40 media utilizes three different medias that are arranged from the coarsest to the finest - a depth loading arrangement allows for particulate to be captured throughout the depth of the media unlike 'strainer' type pleat media that typically utilizes only the surface to capture dirt. This difference is how the TRI-DEK 15/40, with a non-linked 'flat' panel construction without antimicrobial treatment, is able to out perform a pleat.TRI-DIM TRI-DEK 3-ply filter technology eliminates the risk of unfiltered air bypass around or between filters or the between the filter and the filter rack. TRI-DEK utilizes a selvedge edge to provide self-gasket unlike cardboard-frame filters that do not seal and allow unfiltered air to go around the filter. Dirty air bypass is one of the leading causes of coil fouling and can also result in reduced service life of expensive final filters. If only one filter bank is utilized, unfiltered air bypass results in no protection from biological agents and microbial contaminants-both are important concerns in today's world.