Internal blower delivers 550 Max Blower CFM (less than 300 CFM when using reducer), Four 20 watt halogen lights (included) provide unparalleled lighting over and around the cooktop, Telescopic flue accommodates 8' to 9' ceilings -- optional flue extension available for ducted and non-ducted applications, Non-ducted kit for indoor recirculation (sold separately); order replacement filter to keep the kitchen fresh, Multi-speed slide control allows you to choose the perfect speed to keep up with whatever you are cooking, Heat Sentry(R) detects excessive heat and adjusts blower speed to High automatically to prolong product life