The Broan Elite Custom Power Pack is designed to fit flush with the bottom of a cabinet or custom hood that"s 30 to 48-Inch wide. The 400 CFM centrifugal blower is combined with a multi-speed control to provide quiet and effective performance. 400 CFM internal blower provides the power you need at 9.0 Sones, using 6-Inch round ductwork for easy installation. Multi-speed slide control allows you to set just the right exhaust speed to keep up with whatever is cooking. Dual 50-watt Halogen lamps (GU10, MR16, 50-watt max included) provide brilliant lighting over the cook top and surrounding area. Dishwasher-safe aluminum filter features a quick-release latch and professional style appearance for good looks and a fresh kitchen. Optional non-duct filters (FILTEREB40) must be used for indoor exhaust recirculation; some ductwork required. Optional stainless steel liners complete the custom look of your hood and protect surrounding cabinetry (for 18-Inch-21-Inch deep cabinet - RML7030S, RML7036S or RML7048S; for 21-24-Inch deep cabinet - RML7030L, RML7036L OR RML7048L sold separately). Heat Sentry adjusts speed of blower to high automatically in case of excess heat, to prolong product life. Compatible with optional Broan Make-up Air Dampers (MD6TU or MD8TU, sold separately) to fit 6-Inch or 8-Inch ducting and help to balance the air pressure when the range hood is in use, keeping your environment comfortable.