Ruskin model DFD-LP Low Profile, Low Pressure Drop Dynamic Fire Damper is designed for dual directional air flow. The damper is constructed with an integral sleeve/frame and an aerodynamic shaped blade for high-velocity applications. According to the company, the DFD-LP can withstand a maximum velocity of 4,000 fpm and maximum 4-in static pressure. The Ruskin DFD-LP unit can be installed vertically in walls or horizontally in masonry floors.