This is a black insulated binding post. These binding posts do accept banana plugs, 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 red binding post.
Based on 2 ratings:
2 of 2 found this helpful:
Hard to seat and don't lock on to boards and hold as you tighten. Connection was buggy until I overtightened it, worked in the end, but not well. Didn't try banana plugs on, but the pin screw down connector doesn't hold pins well at all.
1 of 1 found this helpful:
The plastic feels cheap, isn't very precise and as a result the screw is hard to turn. The hole in the post is also far from the flat part, so clamping a wire in it usually ruins the end of the wire. I put this next to red posts bought on mouser and the difference is night and day, spend an extra 20 cents to get something better than this