Rockler Woodworking 4-Piece Router Table Accessory Kit: Our 4-Piece Router Table featherboard kit includes an easy-mount dust port, plus three featherboards for more consistent cut quality and to help prevent kickback. Two of the featherboards mount to the fence, exerting pressure down toward the table, while the third mounts to the table and keeps your work against the fence. --- Featherboard Router Table Kit Features: Dust port for router table fence has a 2-1/2'' OD (2-1/4'' ID) hook-up - Table mounted featherboard which fits miter slot openings of 3/8” deep x 3/4" wide, can be secured anywhere along the miter track with the twist of the knob - Fence-mounted featherboards slip into the accessory T track, and are easily adjustable without tools. --- Tech Specifications: Dust Port OD: 2-1/2'' - Dust Port ID: 2-1/4".