• MERV 8 3 Ply 6/15/40 denier synthetic premium grade panel filter with 9 gauge internal wire frame. A dry open web is on the air entering side serving as a 1st stage prefilter catching larger particles. Smaller particles are caught by the 2nd ply of finer denier fibers, which is treated with a non-migrating encapsulating tackifier on the inner layer ensures positive dust holding capacity Dry tightly woven exiting layer encloses tackifier and prevents any bypass or fiber break off. Used for commercial and industrial applications requiring higher levels of performance.