The Big Horn 11133 is 2-1/4 inches wide on one end to work with your shop vac accessories and 2-1/2 inches on the other to be able to thread onto a 2-1/2 inch dust hose for your dust system. Features: Durable Plastic Construction Fits many different brands of Vacuum's What's in the Box: Big Horn 11133 Shop Vac Fittin...