Blue Seal [Jack Pot Vender] © 1929 Watling Manufacturing Co.
Style 51, Quarter Play.
The Jack Pot Vender Style 51 was sold $95 in 1929. The new price in 1930 was $75.
Also released as a Nickel Play model called "Blue Seal [Jack Pot Vender] [Style 41]".
Collector's Treasury of Antique Slot Machines from Contemporary Advertising - Peter Bach - Page 31 & 47