Plug-in, permanently lubricated motor engineered for continuous operation; Dynamically balanced centrifugal blower wheel for quiet, efficient performance; Maintains a high percentage of rated CFM in less than ideal installations; Innovative grille design; Rugged 26 GA galvanized steel construction housing; 6 IN round ducting for superior performance; Polymeric duct connector with tapered sleeve and no metallic clatter; Sturdy, easy, four-point mounting directly to joist; Includes unique spacer (patent pending) for mounting to engineered "I" joists; Includes hanger bars to position housing anywhere between 16 - 24 IN on-center joists; Two sets of mounting holes for hanger bars allow flush installation with bottom or top of drywall; Can be mounted in ceilings up to 12/12 pitch; 3 YR warranty