Big Horn 4 x 2-1/2 in. Hose Reducer is designed with precision to ensure a fit for your shop vacuum. The inside diameter of the 2-1/2-inch side matches the opening on your shop vacuum, allowing you to insert the vacuum hose directly into the fitting with ease. Its outside diameters are crafted to align with standard dust collection hoses, enabling it to function seamlessly as a regular reducer. This thoughtful design makes it an essential accessory for efficient dust collection and vacuum hose connections. Model Number: