INCLUDES: 4 inch to 3 inch dust collection reducer (1pc) 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 4” OD ports or adapters, a 4”flex cuff, POWERTEC 70149, will be needed. EASY TO USE: Offers a 4” OD profile with tapered port on one side, fits inside most 3" dust collection hose PREMIUM QUALITY: Made with heavy duty ABS 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 | 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.Tough, durable ABS plastic material.4-Inch nominal end measures 3-15/16-Inch O.D. and 3-45/56-Inch I.D..3-Inch nominal end measures 2-63/64-Inch O.D. and 2-23/32-Inch I.D., Weight: 0.21 pounds, Manufacturer: Southern Technology LLC