Perfect for boosting air flow in long runs of ducting. Come completely wired with junction box, strain relief and power cord. Energy efficient and very quiet. Lightweight and easy to install. Fluted on both ends to receive ducting. Boxed in retail friendly packaging. 1 year warranty. EcoPlus Inline Duct Booster 4″ – 70CFM EcoPlus Inline Duct Booster 6″ – 160CFM EcoPlus Inline Duct Booster 8″