Models C and H were built at Joliet; with the move to Kalamazoo, Checker introduced the Model H2. The Kalamazoo factory opened on June 23, 1923. Models E, F, and G followed; all of these early taxicabs were based on the original Commonwealth Mogul design. Model E was offered as a five-passenger vehicle from 1924 to 1926 with a choice of three body styles: Landau, Limousine, or Roadster. The Model F was introduced in 1925 and could be distinguished from the Model E by its raked windshield, and the Model G, introduced in 1927, offered an optional six-cylinder engine for the first time. At Kalamazoo, bodies were built at the former Dort factory on South Pitcher Street, then shipped to the former Handley-Knight factory on North Pitcher Street where the chassis were built, being integrated at North Pitcher as each finished chassis rolled off the line. Model K (1928) There were major changes at Checker with a truly new model, the Model K, introduced on October 4, 1928. An advanced, modern design for its day, it was now a purpose built taxi with luxurious town car styling cues. The body was integrated in its design bumper to bumper; no longer did it possess the Commonwealth Mogul front clip mated to a taxicab body first introduced in 1918. The Model K was Checker's first ground-up design, introduced 6 years after the founding of Checker. Consistent with previous Checkers, the Model K utilized a 127-inch wheelbase and the Buda six-cylinder was now the only engine available. Within the first month of introduction, there were over 4,800 orders. By January 1929, 950 units had been produced and sold. At the end of January 1929, over 8,000 Checkers were chasing fares in New York City, a city with a total population of 21,000 cabs. This made Checker one of the two dominant taxicab builders in the US, the other being Yellow Cab Manufacturing. Together, the two taxicab manufacturers pushed the other taxicab producers, Premier, Pennant and HCS, out of the market. These two taxicab giants would slug it out through the next decade. Model M (1930) The Model M was introduced in late 1930; compared to the Model K, the M had front fenders that pointed straight forward, carried headlights set in rectangular bezels, and rode on a wheelbase shorter. The M carried a more powerful Buda J-214 six-cylinder engine with , more than