POWERTEC 70124 Universal Dust Port, 2 1/2" Designed to attach easily and securely to machines for connecting to dust collection systems Made of superior, durable ABC plastic material Opening 2-1/2-Inch nominal end measures 2-15/32-Inch tapered O.D. and 19/64-Inch I.D. Flange end measures 3-5/8-Inch by 4-Inch