The Koch Multi-Sak™ is an extended surface air filter designed for most medium and high efficiency air filtration systems. The Multi-Sak™ is capable of operating in systems with rated face velocities of 500 to 3000 cfm. Available efficiencies range from 20% to 95%, and seven standard face sizes are offered. This broad spectrum of styles and models makes the Multi-Sak™ extremely versatile and suitable for almost any commercial or industrial air handling system. Koch Filter® Extended Surface Pocket Bag Filter, High Efficiency, Series: Multi-SAK™ Series S, 20 in Width, 22 in D, 24 in Height, MERV: MERV 12, 1000 to 1400 cfm, 60 to 65% Efficiency, 5 Pockets, 0.39 in WG Initial Resistance, 1-1/2 in WG Final Resistance, Synthetic Fiber Media, White, Domestic