They thus founded Filterwerk MANN+HUMMEL GmbH in 1941 and employees produced fabric filters for the automotive industry.

Customers include Maybach-Motorenbau with the HL230 engine, used on Panzer tanks such as Panther and Tiger.

[1] After the end of the war, in 1945, a branch was opened in Ludwigsburg, followed by Bösperde (1946) and Marklkofen (1962).

[2][3] From the late 1940s onwards, MANN+HUMMEL was also active in the textile industry under the name Mann Pamina Moden, before this line of business was sold to Schiesser in 1974.

Since 1948, there is further diversification beyond filter production through the equipment manufacturing division, particularly for the plastics industry.