Read the features carefully - or be disappointed...

This connector is female on both ends. I didn't pay close enough attention to the description while shopping and ordered it expecting to be able to connect my 2 1/2" shop-vac hose to the 4" dust collection port on my table saw. Needless to say, I was dismayed to discover the diameter of this adapter and the port on my table saw were the exact same OD - meaning it doesn't fit without a 4" hose between the two.^M
^M
If you do end up in the same situation as me - don't give up hope. I aligned the adapter and DC collection and wrapped a length of duct tape around both. A solid connection that converts my tablesaw from 4" to 2 1/2" and works great! Hope that helps those who were in the same situation as I. For those who have yet to purchase, just make sure this is really the product you are looking for. ^M
^M
In case anyone is really concerned, the actual construction of this adapter is solid and accurate.

Size is important

The 4" side fits my 4" quick release well enough. The 2 1/2" side fits the END of a 2 1/2" hose. This does not work well if you intend to go directly from your 2 1/2" port on your machine to your 4" dust collection hose. The adapter and the port will more than likely be the exact same size (two female sides).^M
The adapter is also not shaped the same as in the picture. It is not funnel shaped but a 2 1/2" tube and a 4" tube connected by a flat piece.

Perfect for the dewalt table saw

Inially I was upset with this, it didn't fit. Well, my mistake, I didn't see the OD part. Anyway, I found the perfect spot. It fits the 2 1/2 inch port for the Dewalt table saw perfectly. I have now replaced the elbow fitting that came with the saw that for some reason is set to point at the saw leg, making it useless. Now my saw is easy to connect to my 4 inch collection system.