FUNCTION: This dust collector attachment possesses a 4-inch OD end that connects to standard 4-inch ID dust collection hose and allows you to step down to a 3 inch dust collection hose or line branch. Note: to connect to other 4inch OD ports or adapters, a 4inch flex cuffEASY TO USE: Offers a 4inch OD profile with tapered port on one side, fits inside most 3inch dust collection hosePREMIUM QUALITY: Made with heavy duty plastic material for long-term durability and made to withstand the abrasive nature of woodworking and workshop dust collectionDIMENSIONS: 4-Inch o.d nominal end to 3-Inch o.d nominal endConnect 3-Inch opening duct to 4-Inch flexible hose ition 3-Inch duct to 4-Inch standard hosePlease note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you!Colour:As ShownMaterial:plasticPackage Contents:1 x 4 inch to 3 inch dust collection reducerOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.