I bought six of these because I have a Shop Vac fitted out with 2-1/2" connections and stationary equipment with discharge ports varying in size from 3-inch down to 1-1/2-inch. I have hose ranging from 2" to 3", to get the dust and shavings from a planer, miter saw, table saw, and router table, and I could rig up the bench grinder, too. Of all the combinations possible, one succeeded.