This is a split-bracket bracket-mount slide-rule dial pointer (part #0194). It features a 3/4" x 5/8" mounting base with a 1/2" open center channel between the left and right mounting brackets, designed to clip onto or ride along a guide rod, track, or dual drive-cord mechanism. This design extends a 4 1/8-inch indicator needle across the glass or illuminated dial scale and was commonly used in mid-century tabletop and console tube radios manufactured by companies such as Philco, Zenith, RCA Victor, General Electric, and Crosley.