This is an upward-pointing slide-rule dial pointer (part #100201). It features a base mount designed to attach to a slider track, drive cable, or dial string, extending an upward-facing indicator needle across horizontal slide-rule glass dial scales. This design was engineered for station tracking in 1930s through 1950s tabletop and console tube radios manufactured by companies such as Philco, Zenith, RCA Victor, General Electric, and Crosley.