What is "tune-o-matic"

Tune-o-matic (also abbreviated to TOM) is a name of fixed bridge design for electric guitars. It was designed by Ted McCarty ( Gibson Guitar Corporation president) and introduced in the Gibson Super 400 guitar in 1953 and the Les Paul Custom the following year. In 1955, it was used on the Gibson Les Paul Gold Top. It was gradually accepted as a standard on almost all Gibson fixed-bridge guitars, replacing the previous wrap-around bridge design, except on the budget series.