Cadillac's single-cylinder line-up was consolidated into two models for 1906, the short wheelbase Model K and long wheelbase Model M. Priced at $750 for the Model K or $950 for the Model M, 3,650 units were sold that year. The K and M were essentially similar to the Models E and F from 1905 but with updated bodies. Model M had a ten horsepower 98 cubic inch horizontal single-cylinder engine with 2-speed planetary transmission and chain drive.
Production and sale of the Models K and M continued in 1907.
The Model M continued as a commercial delivery vehicle for 1908, priced at $950.