In the Season 5 episode of I Love Lucy entitled Lucy Hates to Leave Lucy is awake at night worrying about the move to their new house in the country. On the bedroom shelf there is a hexagonal alarm clock.
The shape and dial of the clock is an exact match for the white dial verson of the Telechron “Dorm” alarm clock. A closer look at the clock in the screen capture reveals it to be missing the cover in front of the dial. With the cover removed we notice clips at edges of the clock face to keep it in place. Pictured below is a black version of the same clock on Etsy (US) and from the photo we see how the window in front of the dial is curved and catches the light and would be too reflective for the studio lights- a practical reason for removing the front cover on set.