Brackets
Brackets in fencing can mean several things. It could mean extension brackets that are attached to a fence, or standalone brackets that are used for wall top security with barbed wire, razor wire or electric fence.
Brackets could also mean fittings that are used to attach fence panels to posts, or used to attach fencing to a wall or another structure.
Fence brackets are usually made from steel, but they could also be made from plastic or nylon, depending on how they will be installed and used.