Abstract: A tool for use with a locking mechanism of an instrument setup of a stringed musical instrument comprises a body having a longitudinal axis, a transverse axis, a first surface extending along the longitudinal axis, and a second surface substantially parallel to the first surface of the body. The tool also includes a key disposed on the first surface and extending substantially along the transverse axis and a magnet disposed on the second surface of the body is configured for being received within a socketed head of the locking mechanism of the instrument setup system. The magnet is configured to be attached to a magnetic surface on the stringed instrument to hold the tool in place during use for “one handed” operation.