This O-Z/Gedney 31-400 compression connector is perfect for use with 4 inch rigid metal conduit (RMC). The connector is made of malleable iron that has been zinc plated for added durability. This accessory is designed to securely connect two lengths of conduit together, making it an essential component in any electrical system. The connector features a compression connection type, which ensures a tight and secure fit between the conduit and the connector. It is manufactured in the United States to ensure the highest quality standards. Whether you're setting up a new electrical system or making repairs, this O-Z/Gedney compression connector is the ideal choice.