FIG. 1 is a front perspective view of a back brace, showing my design.

FIG. 2 is a rear perspective view of the back brace of FIG. 1.

FIG. 3 is a front elevational view of the back brace of FIG. 1.

FIG. 4 is a rear elevational view of the back brace of FIG. 1.

FIG. 5 is a top plan view of the back brace of FIG. 1.

FIG. 6 is a bottom plan view of the back brace of FIG. 1 .

FIG. 7 is a first side elevational view of the back brace of FIG. 1; and,

FIG. 8 is a second side elevational view of the back brace of FIG. 1.

The broken lines illustrate environmental structure which forms no part of the claimed design.