Use the WoodRiver® Dust Connection™ 1-1/2" to 2-1/4" Adapter Fitting to connect a smaller diameter hose to your common shop vacuum. Rugged ABS material is nominal 2-1/4" OD on one end to slide inside the suction port on most shop vacuums and nominal 1-1/2" OD on the other end to connect common 1-1/2" hose or other 1-1/2" ID fittings. Features: Specifications: What's Included: