Probak was a brand of safety razors and blades started by Henry J. Gaisman
in 1928. Gaisman, the founder of Auto Strop
, received a patent for his new double-edge safety razor and blade design in 1927, and supplemented this with a 1929 trademark on the Probak blade design. Probak blades were designed to be compatible with Gillette "Old" and "New Improved" razors, but Probak razors would not accept the three-hole Gillette blades. A 1930 lawsuit with Gillette disputed their NEW
design, and ended with Gillette acquiring Probak and Auto Strop. As a result, Gaisman became chairman of Gillette in 1931. Probak razors continued to be sold as late as 1936 and Gillette used the Probak brand for blades as late as 1945.
A story relates that the Probak name was intended to be pronounced the same in all known languages. In many languages "probak" also has no meaning of its own, but in Basque it means "tests".