This is a slide-rule base-mounted dial pointer (part #0185). It features a flat rectangular drive-mounting base designed to attach directly to a tuning cord, slider track, or drive cable, extending a straight 3.5-inch indicator needle across the glass or illuminated dial scale. This style was commonly used in mid-century tabletop radios, consoles, and receivers manufactured by brands like Philco, RCA Victor, Zenith, Emerson, and General Electric.