Dome caps
Dome caps are rounded metal caps that are used on the top of round fence posts in North America.
Dome caps can be made out of aluminum or steel, and they can be powder coated to match the color of your fence. They fit tightly over the outside of the fence post, and aside from esthetics, their most important job is to keep water out of fence posts.
Dome caps are usually used on gate and terminal posts on chain link fence, but they can be used on other fence types that use round tubular posts.