Displays objects as boxes that represent their bounding volumes. Bounding boxes speed up Maya operations and can make a significant difference for complex models.
The bounding box encompasses the hulls as well as the actual geometry. As a result, the bounding box may have dimensions larger than those of the geometry.
To see bounding box coordinates, open the Attribute Editor, click the shape node tab, and open the Object Display section. It shows the read-only minimum and maximum world space boundary coordinates of a surface along the X, Y, and Z axes.