Engelkemper II 1966 page 182
Junghans catalog 1914 text:
open faced Junghans "Master" Watch, 15 jewels,
cut compensation balance, hardened breguet steel hair spring, lever escapement with visible jewels, steel escape wheel, double safety roller, gilt plates gold or silver.
The watch will come with the factories certificate of warranty.
A new click spring like later in the J47. Should be around 1929.