The F40000 Series Provides Installation Flexibility With 4-Way Convertibility To Fit Virtually All Applications. The Hood Is Designed For Under Cabinet Use And Installs As 3-1/4 In. X 10 In. Ducted Opening With Vertical Or Horizontal Ducting; Or 7 In. Round Vertical Ducting Or As Non-Ducted With Air Recirculation. The Hood Features A Fan Designed For Years Of Trouble Free Service, An Easy To Clean Grease Filter, A Protective Lamp Lens That Distributes Light Evenly Over The Cook-Top And Control Switches For Fan Speed And Light Activation.