1.Specification: Color: Silver Tone; Material: Galvanized Iron; Interface Outer Diameter: 73 mm / 2.9 inch; Diagonal Mounting Hole Distance: 88 mm / 3.5 inch; Distance Between Adjacent Mounting Holes: 43 mm / 1.7 inch; Base Outer Diameter: 98 mm / 3.9 inch; Height: 47mm/1.9 inch; Packing List: 4 Pcs x Duct Connectors 2.Advantages: 1. The connector is made of galvanized iron, which is anticorrosion, coldresistant, hightemperature resistant, not easily deformed, and durable. 2. The base of the connector has screw mounting holes, and it can be directly fixed on the wall with screws, which is easy to use. 3. The surface of the ventilation flange is smooth, which is conducive to connecting the air duct. 3.Instruction: Screw the flange securely to the air inlet, air outlet, wall, ceiling or other surface for connecting to the ventilation system. 4.Application: The duct flange is widely used as air inlet and outlet connector in ventilation systems, suitable for ducting your air conditioning system, dust collection system, tumble dryer, extractor fan, exhaust fan, inline extract fan, cooker hood, and so on.