Dorr Eugene Felt (Artington, Wisconsin, 1862 – Chicago, 1930) builds the first functional Comptometer prototype in 1885 — known as the "Macaroni Box" prototype for using a macaroni box, corks, and rubber bands — and obtains the patent in January 1887 (US Patent 371,496). The Comptometer is the first practical, commercially successful direct-key-driven calculator: the operator presses the numeric keys of the addend directly, with no intermediate levers. Felt founds the company Felt & Tarrant Manufacturing in 1889. Unlike all earlier inventions in the chain, the Comptometer was mass-produced and used in real accounting settings for decades: it is the first link to reach the labor market directly.