Durable material: clean and shiny white plastic, lightweight and anti-rust Diameter 80/90/100/110/120 mm gradually decrease or increase.then slide them together. Easy! Tape or flexible hose clamps may be required for a perfect seal. Cutting tools are not included, we recommend a saw. This is a very practical and robust reducer or amplifier for fixed channels that can be used when two different fixed or flexible channels are connected to fans or vice versa, from small to large, from large to small Can be used with HVAC systems: bathroom fans, in-line fans, kitchen hoods, tumble dryers, hydroponics, kitchens or anywhere in the apartment, home or office. Installation: Measure the different diameters of the ducts and cut the duct reducer to the desired size. Plug the duct connector into or onto the pipes,