I recently purchased some of these: [Digi-Key Banana Jack](http://www.digikey.ca/product-detail/en/0/501-1228-ND). Unfortunately, I'm new and there isn't the supporting documentation I need to be able to determine how they're to be used. 

![Side view](https://i.stack.imgur.com/ZN9pC.jpg)
![Bottom view](https://i.stack.imgur.com/jGbjo.jpg)
![Top view](https://i.stack.imgur.com/0ohsU.jpg)

Unlike other banana jacks, there is not a hole to feed the wire through and screw down on. I understand the large nut is for holding it against the enclosure, but I don't know what the intention is with the threaded bottom section and the two nuts. I'm guessing that the wire is simply looped around and a nut is tightened down against it, but this doesn't seem very durable. Why the double nuts, what is supposed to be done with them?

*Edit*
To clarify, I understand that they are the female piece of a banana connector. I have male banana connectors that I am using these with. My lack of understanding comes from how to wire this female piece to the... for lack of a better word "connection wire". I.e. how to wire this female portion into a circuit so that the circuit is accessible through it.