This is a basic insulated binding post – these are seen on everything from basic power supplies to the backs of bookshelf speakers. Connections to these can be done by way of banana plugs into the top or bare wires into the threaded clamp and are a great way to connect single-wire leads. The colored cap screws up and down, and is designed to clamp on the connecting wire. These binding posts are sold individually. We also carry a similar black binding post.