This adapter works great for what it is designed for. It is only for changing 4 inch hose to 2 1/2 hose. Not designed to connect directly to a tool or shop vacuums. Usually the 2 1/2 inch hose will connect to the tool.

As another reviewer said..... this is the exact same size as the tool port I have.... it is NOT four inches, but slightly less. If it were exactly four inches, it would have worked.... if it were funnel shaped, it would have worked, but it's the exact same size as my dust port. it will not fit over , or inside my dust port. The industry needs a better explanation for dust port sizes.... This has caused me agravation a few other times on shop vac and other tool dust port sizes.

Gene

If I had known that this was included with the Dust Hood I would not have ordered it. It is now in excess of my requirements.

There seems to be some confusion/frustration about this item so consider if this is the item you actually need. This product is not designed to go directly from a 2 1/2" dust port to a 4" hose. If that is what you want get the Jet JW1000 4-Inch to 2-1/4-Inch OD 2-Inch ID Reducer

2 1/2" dust ports typically have 1/8" thick plastic which creates an interior diameter (ID) of 2 1/4". I own the JW1000 adapter and it fits perfectly into/inside my 4" dust collection hose and into/inside my 2 1/2" port on an oscillating spindle sander. Delta has an equivalent adapter (Delta P/N 50-482) but I do not own it so I can't recommend for or against it.

Consider your application, measure the diameters, and then choose the adapter that fits your need.

I use this almost daily when I swap the dust collector hood next to my lathe for a hose fitting to vacuum up all the chips that went elsewhere. I have a quick connect fitting on the 4" hose to easily swap it from the hood to this reducer. This reducer is such a tight fit that I can barely get it deep enough in the mating fitting to hold. It pops out easily just on the weight of 6' of 2 1/2 in hose.