Designed for installations where conventional ventilation simply won't fit. Where multi family applications require it, the LoProfile™ fan is narrow enough to be installed in a wall between 2x4 studs. When plumbing or electrical obstructions are found behind the drywall in ceiling remodel applications, the LoProfile™ fan can still fit without having to move anything. And that means most any room with space constraints can have powerful, quiet efficient ventilation. Fits in 2x4 ceiling or wall construction. 110 CFM at 0.1 static pressure and 90 CFM at 0.25 static pressure. Only 1.5 sones for extremely quiet operation. 4 oval or 3 inch round duct connection for installation flexibility. ENERGY STAR® qualified for efficient operation and lower utility bills. Ideal for multi-family applications. Plug-in, permanently lubricated motor - engineered for continuous operation. Can be used with RDF1 radiation damper.