irguard's Activator series air filters have multi-stage media construction with layers of multi-denier polyester fibers that capture particles throughout the filter's depth, preventing "face-loading," and increasing dust-holding capacity. The filters are manufactured in two-, three- and four-ply models to meet MERV 6, 7 and 8, respectively. Media layers are heat-sealed around a nine-gauge internal wire frame. Cross-wire supports are welded to the frame. Activators can be installed with cross wires in vertical or horizontal positions. They are rated for continuous use up to 220