Chemco 20"x25"x2" FMP-18 Fiberglass Paint Spray Booth Exhaust Filter Pads 100/CaseRequired minimum quantity: 4 cases Maximum quantity: 28 cases The Chemco FMP 18 has a unique micro filament fiber structure that increases the area and optimizes air flow. FMP 18 contains 33% more fiber strands than a standard fiberglass filter thanks to the smaller fiber diameter. An open weave design promotes depth loading while the heavy weight provides maximum efficiency with little impact on cost. These filters have an efficiency of 99. 07%. FG