This is a double-ended Fahnestock clip (part #151009). It features two spring-action terminal connectors mounted back-to-back on a single metal strip with a central mounting hole. Designed for quick, solderless wire connections, Fahnestock clips were widely used in early 20th-century radio equipment, crystal sets, breadboard circuits, and educational electrical apparatus produced by manufacturers like Atwater Kent, Crosley, and General Electric.