Shoemaker 845-18X8 18"x8" Stamped 3-Way Diffuser - White 845 O - Steel Lever Operated Opposed Blade Damper All Component Parts, Rivets, Linkage, And Handle, Are Enclosed In The Valve To Assure Trouble Free Operation Countersunk Mounting Holes For Flush Appearance With Color Matching Phillips Posi-Drive Screws For Ceiling Or Sidewall Applications