Zenith Dial Lamp Shade
Dimensions: 1" x 1-5/8"
Used on Zenith, RCA, and a few other brands. These are used for deflecting heat away from the dial so that the dial lamps don't burn a spot in the dial. They also help diffuse the light.
Some of the 1939 Zeniths used these dial shades, usually 6-tube or fewer tube radios from 1939. (Only used on backlit plastic dials.)
Be sure to use only #47 bulbs with your back-lit translucent dials. For the METAL dial radios like the Zenith Shutterdials, use a #44 or # 55 bulb. For older radios with screw-in bulbs, use a #40 bulb if the dial is back-lit. For 2.5v. Filament radios (everything before 1934) use #41 bulbs.