There are 3 styles in the Westclox Zobo Style Series
Oval bow, pendant spaced slightly away from case body.
Dates made: ca. 1938
Earlier style hands, short pendant.
Dates made: ca. 1948
Uses the same hands as the later Scotty pocket watches (Dauphine minute hand, alpha hour hand).
Dates made: ca. 1950 - 1960