Panel instrument

A panel instrument to be mounted in a panel board, the panel instrument comprising:

• a main body having an outside dimension that is applicable at least to a first panel instrument size standard and a second panel instrument size standard;
• a display section provided on one end of the main body and having an area that occupies a part of a front face of the panel board, the area being applicable to the first panel instrument size standard;
• a front panel mounted on a front face of the display section;
• and
• a rear panel for holding the display section in association with the front panel, wherein the rear panel has:
• first mounting holes that are provided on one diagonal line of the rear panel and correspond to a mounting hole standard applicable to the second panel instrument size standard;
• and
• second mounting holes that are provided on the other diagonal line of the rear panel and correspond to a mounting hole standard applicable to a third panel instrument size standard;
• wherein the rear panel is rotatable to further utilize different pitches of first and second mounting holes, or different shapes or sizes of the panel cutout hole.