This is a slide-rule base-mounted dial pointer (part #120525-1). It features a 1 1/4" x 5/8" rectangular drive-mounting base designed to attach directly to a tuning cord, slider track, or drive cable, extending a straight 1 3/4-inch indicator needle across slide-rule glass dial scales. This style was commonly used in tabletop radios, compact receivers, and consoles manufactured by brands like Philco, RCA Victor, Zenith, Emerson, and General Electric.