Support arm

FIG. 1 is a perspective view of the support arm showing my new design;

FIG. 2 is a perspective view thereof from another angle;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a left side elevational view thereof;

FIG. 6 is a right side elevational view thereof;

FIG. 7 is a top plan view of thereof; and,

FIG. 8 is a bottom plan view of thereof.

The broken lines depict portions of the support arm that form no part of the claimed design.