The configuration of the Kluson tuners used on Gibson instruments can be used to date an instrument. Before 1959, all Kluson tuners with plastic buttons had a single ring around the stem end of the button. In 1960, this was changed to a double ring configuration. Early 1950s tuners have no writing in the center line. Mid-1950s to late 1950s production features Kluson deluxe tuners with single line marking. By the mid-1960s, a two-line marking states "Kluson Deluxe."