Some of the most successful telegraph keys in U.S. history were the steel lever keys made by J.H. Bunnell & Co. They were produced by the hundreds of thousands, copied by many manufacturers, but because they are so seemingly common, are typically ignored by collectors, and frequently sit unclaimed at the close of flea markets. Most of these keys have been incorrectly pigeonholed into a common category called "Triumphs".

The steel lever key patented by Jesse Bunnell in 1881 was not called the "Triumph Key", although the steel lever design was certainly a triumph for his company due to its popularity. The top of the line key that was specifically called the "Triumph" did not show up until twenty five years later.

As early as 1868 inventors and makers were experimenting with various lever designs attempting to solve the problem of a brass lever becoming loose on its steel axis when subject to consistent lateral pressures. This lateral movement produced a secondary problem called "sticking" that occurred when the lever was released. The key contacts would slide back across themselves instead of breaking clean especially when closely gapped. The heavier brass lever designs of the 1870's were actually an attempt to minimize this problem, but the trade off was a heavy, less responsive lever. During the 1870-1880's makers, including J.H. Bunnell & Co., promoted the cure of "sticking" with their new designs.