Watling was the third largest maker of slot machine before World War I. Watling stayed in the competition with imitations and lower prices, though they did come up with a few innovations of their own designed for the operator. Then when Mills introduced their wooden-sided OPERATORS BELL in 1915, they also manufactured it. Around 1911 they copied the new Caille FUTURE PAY BELL and OPERATORS BELL and sold them less price than Caille. To be a competing manufacturer and get a share of the growing bell machine market, it was necessary for Watling to add this slot to their expanding line. They also began creating a few floor machine of their own design, including the MARQUETTE and the DERBY. Watling Manufacturing Company increased slot line by making their own versions of the successful Mills and Caille slots.

In late 1901 the Watlings incorporated with Tom as president and John as secretary, and purchased the D.N. Through this work they came into contact with Daniel Schall, who in 1895 introduced a version of the Schultze automatic payout counter wheel to Chicago. Watling who was a founder of Watling Manufacturing and his older brother John, both Scottish immigrants, had begun their enterprising careers selling carnival games and equipment.