Chamberlain Wrench Company (Bizmark, ND) - Incorporated April 1913 to manufacture John W. Chamberlain's patented wrench - Patent #1,042,318. Incorporators are John W. and Minnie J. Chamberlain and G. F. Dullam. Mr. Chamberlain also applied for a patent for a combination claw hammer and plier multi-tool in 1906, however we cannot find that it was awarded.