Check the listing for details. WOODRIVER Dust Connection 4" to 2-1/2" Basic Reducer Blast Gate Fitting. Condition: New. Listed at 21.98 USD. WOODRIVER Dust Connection 4" to 2-1/2" Basic Reducer Blast Gate Fitting, 173019, SIMPLE OPEN OR SHUT design has plate inside frame, Basic blast gate fitting shut off one branch at a time, 8-1/2" x 7-1/2" closed and 14" x 7-1/2" when open, 4" OD port is 1-1/2" long; 2-1/2" OD port is 1-1/4" long, MOLDED USING ABS material for rigidity and durability, WoodRiver Dust Connection ABS Basic Reducer Blast Gate Dust Collection Fitting allows you to close one branch of your central dust collection system while you are using the other. The simple open or shut design has a flat, square plate that moves inside a 3-sided frame to provide a pass-through or shut-off to connect your dust collector to your system or a branch line to one of your tools. Molded fitting has overall dimensions of 6-1/2" long.