This duct reducer can be used in connecting two different sizes of duct to create a seamless ventilation system duct. Suitable for HVAC systems, dust collectors, inline ventilator, cooker hoods, bathroom exhaust fans, hydroponic equipment, etc. Meet different environment needs, such as kitchen, home, office, factory, or apartments.Specification:Material: ABS PlasticInner Diameter 1: 94mm/ 3.7 InchOuter Diameter 1: 99mm/ 3.9 InchInner Diameter 2: 150mm/ 5.91 InchOuter Diameter 1: 155mm/ 6.1 InchLength: 113mm/ 4.45 InchThickness: 2.5mm/ 0.1 InchPackage List: 1 Pcs x Duct Reducer, 2 Pcs x 304 Stainless Steel Hose Clamps (Inner Diameter: 91mm-114mm/ 3.58"-4.49", 155mm-178mm/ 6.1"-7.