Horizontal and vertical installation possible. Flow direction with vertical installation from bottom to top. With 2 opposing flap halves made of aluminum. With all-round seal. Check valves open in the air flow and close via spring force. Article: AVM 40, Air direction: ventilation or exhaust, Installation position: vertical / horizontal, Material: Sheet steel, galvanized, Weight: 2.6 kg, Weight with packaging: 2.63 kg, Flap type: self-opening/closing, Nominal width: 400 mm, Width: 398 mm, Height: 398 mm, Depth: 198 mm, Width with packaging: 398 mm, Height with packaging: 398 mm, Depth with packaging: 198 mm