Durable Material: Made of clean gloss white lightweight plastic and is rust free.This is a very practical robust, solid duct reducer or increaser which can be used when connecting two different, solid or flexible ducts or ducts to ventilators, or vice versa, from small to large, larger to small.bathroom extractor fans, inline ventilators, cooker hoods, tumble dryers, hydroponics, kitchens or, anywhere else in the apartment, home or office space.Measure the different diameters of the ducts and then cut the duct reducer to the size needed. Insert the duct connector into or on the the pipes and then push them together.Duct tape or flexible duct clamps may be required for a perfect seal. Tools for cutting are not provided, we suggest a saw.