The ornamental design for a casing for a gaugeassembly, as shown and described.
FIG. 1 is a front perspective view of a casing for a gauge assembly according to our new and ornamental design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a first side view thereof;
FIG. 6 is a second side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The evenly-dashed broken lines in the FIGS. 1-8 depict portions of the casing for a gauge assembly that form no part of the claimed design. The dash-dot-dash broken lines in FIGS. 1-8 depict the boundary of the claimed design and form no part of the claimed design.