Aluminium Double Louver Adjustable Grills Aluminium Double Louver Grills: DL Series Truestar Air Systems Double Louver Grills features 2 sets of fully Adjustable blades to provide maximum flexibility in Supplying air into an occupied space. The Front Louvers Can be Horizontal (Model DL201) or Vertical (Model DL202). The Rear louvers have opposite orientation as Compared to the front. They are usually used to supply Air from the side wall. The frame flange has a standard width of 20mm. Model - DL 201 & DL 202 Dimensions - Max Width 1800mm - Max Height 1200mm - Max Blade width 600mm without Vertical Mullion - Fixed to Wall using pan head screws (holes to be drilled at site) MOC Frame - 20mm Flange, 46mm Depth, 1.1mm Thk, Aluminium Extrusion. Blade - 1mm Thk. Aluminium extrusion with 4mm cylindrical Portion to act as pivot.