The earliest Style 4 Chime Alarm dials don't say "Chime Alarm" at the top. Starting around April 1935 the words "Chime Alarm" were added.
Dial No "Chime Alarm":
The dial doesn't say "Chime Alarm". The words "Westclox" and "Big Ben" are printed in the same typeface as on the Style 3 Big Ben Chime alarm. Used from the beginning of Style 4 Big Ben Chime Alarm through ca. April 1935.
Dial "Chime Alarm":
The dial says "Chime Alarm" above the center and "Westclox" and "Big Ben" below the center. Used from ca. April 1935 through the end of Style 4 Chime Alarm production.
