"Anderson Power Poles" are a brand of connectors. There are many models/types available, but the most common for ham radio work is their 1327 series (pix below).
The basic component, the "connector body", is a single piece of plastic in shape of a square tube.
They are manufactured with a spring inserted inside the tube, and when a user assembles them for his application,
a pin with wire are inserted.
Two or more connector bodies can be attached to each other to create a multi-pin connector, like the red and black housings assembled into a two-pin connector above.
There are dozens of different possible configurations, but the most common for ham equipment power connectors
is a red body paired with a black body. Note side-to-side orientation in pix above.
Also note correct orientation of the pins as they are inserted into the connector bodies. The pins will slide in and click.
-------------------------------------------------------