Check the listing for details. WOODRIVER Dust Connection 4" ABS Basic Blast Gate Fitting for Dust Collection Sy. Condition: New. Listed at 21.98 USD. NEW, WOODRIVER Dust Connection 4" ABS Basic Blast Gate Fitting for Dust Collection System, 85O06, Blast gates act as a "shut-off" or valve for the suction from your dust collector, Tapered port each side of the sliding gate fits inside most 4” dust collection hose, Sliding gate has a stop to prevent the plate from coming out of the housing, Constructed of tough abrasion resistant plastic resins, Blast Gate Fittings let you “turn-off” the suction from your dust collector to use other machines connected to other branches of your system. This blast gate has the same tapered 4" O.D. port on either side of the gate so you can place in the middle of a branch hose.Because of the danger of static electricity involved with dust collection we highly recommend reading the book Dust Control Made.