Internal grille with front frame. For installation in spiral-seam ducts. With horizontal, pivoting air deflection blades on the front. Air flow regulated by adjustable slotted damper. Ideally (DN 250 for installation height 65 mm, DN 500 for installation height 115 mm) the internal grille rests completely against the duct. With visible screw holes. Article: LGR 42/6, Air direction: ventilation, Useful air flow rate with 75% opening of the hit-and-miss damper: 150 m3/h - 250 m3/h, Installation: inside, Installation location: pipe, Material: galvanized sheet steel, Weight: 0.82 kg, Weight with packaging: 0.97 kg, Suitable for nominal width: 140 mm - 400 mm (ideally 250 mm), Width: 458 mm, Height: 113 mm, Depth: 56 mm, Width with packaging: 490 mm, Height with packaging: 120 mm, Depth with packaging: 70 mm