Permatron hospital grade prefilter for the Honeywell F52D, dual cell model. The F52D uses one large pre-filter.
Verify your prefilter dimensions, the F52D models were manufactured with different prefilter sizes. This 190910A alternate prefilter measures 30-1/4 x 20-9/16 x 5/16 inch.
For an alternate size see the F52 prefilter 190910 or 198442.
Permatron, the premiere prefilter manufacturer, designed this prefilter to exact Honeywell specs. The metal mesh consists of 5 layers of slit and expanded aluminum of differing densities. The frame is upgraded to stainless steel.