Keuffel and Esser began as a drafting supply company in 1867 in New York, United States of America. Over time, they expanded their product line to include a variety of technical and engineering supplies, including slide rules, which became one of their most iconic products.^[1] In the mid-20th century, Keuffel and Esser diversified into producing aperture cards under the “Micro-Master” brand name.

The company was noted as having over 10000 products in their 1967 catalogue, but ultimately entered gradual decline in the late 20th century due to changes in technology.[1] In 1987 the company was acquired by AZON Corporation and ceased operations as an independent entity.^[2]