The easiest way to connect two electric wires is to strip them and twist their ends together. It’s simple and quick, however such links are not very reliable, and can get broken up or oxidizes, if not protected properly. Insulation tape might be used, but its adhesive component might fall off in time. In such cases twist-on caps are utilized to protect the connection. Hard caps vary in shapes and sizes to match various types of cables. Caps are simply put on the two joined wires and then rotated to fix them in place. These appliances provide good temporary protection, but cannot be used for a permanent connection. More complicated connectors like binding posts and crimping appliances are used for a semi-permanent connection, when the wires can be reattached to these connecting devices relatively easy. And finally there are plugs and sockets - permanent connectors for long-term use. They come already connected to a wire, and are rarely changed.