The true zipper was the product of a series of incremental improvements over more than twenty years, by inventors and engineers associated with a sequence of companies that were the progenitors of Talon, Inc. This process began with a version called the "clasp locker", invented by Whitcomb L. Judson of Chicago (previously of Minneapolis and New York City), and for which a patent was first applied on Nov. 7, 1891. It culminated in 1914 with Gideon Sundback's invention of the "Hookless Fastener No. 2", the first version of the zipper without any major design flaws and essentially indistinguishable from modern zippers. In 1917 a Swiss inventor, Mathieu Burri, invented a better version, but it got rejected because of a previous patent.