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 cuff EASY TO USE: Offers a 4inch OD profile with tapered port on one side, fits inside most 3inch dust collection hose PREMIUM QUALITY: Made with heavy duty plastic material for long-term durability and made to withstand the abrasive nature of woodworking and workshop dust collection DIMENSIONS: 4-Inch o.d nominal end to 3-Inch o.d nominal end Connect 3-Inch opening duct to 4-Inch flexible hose Transition 3-Inch duct to 4-Inch standard hose Please note: the physical slightly color difference or difference, does not affect the use, please do not mind, thank you! Colour:As Shown Material:plastic Package Contents: 1 x 4 inch to 3 inch dust collection reducer Only 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.