Terminal blocks are modular, insulated screw-type electrical connectors that are used to secure and/or terminate two or more wires together. Useful for connecting wiring to a ground or for connecting electrical switches and outlets to the mains. Molded Bakelite and stamped brass construction. Designed for use with tinned copper marine wire which shares the same expansion rate preventing loosening and reducing electrolytic corrosion caused by pairing two disparate metals. Installs with four RH fasteners (not included).