The invention relates to a protective tuner cover for the tuning section of a stringed musical instrument, such as a guitar. The operating method of the mobile terminal includes receiving state information of the refrigerator from the refrigerator, displaying the state information of the refrigerator on a screen, and transmitting a control signal based on a control operation to the refrigerator. The ring can be connected rigidly to the support, or can be connected to the support via a ring positioning unit that is able to translate or tilt the gantry relative to the support on one or more axes.