FIG. 1 is a front, right perspective of a helmet showing my new design;
FIG. 2 is a front elevation view of FIG. 1;
FIG. 3 is a right-side elevation view of FIG. 1, the left side being a mirror image thereof;
FIG. 4 is a rear elevation view of FIG. 1;
FIG. 5 is a top plan view of FIG. 1;
FIG. 6 is a bottom view of FIG. 1;
FIG. 7 is a front, right perspective of a second embodiment thereof;
FIG. 8 is a front elevation view of FIG. 7;
FIG. 9 is a right-side elevation view of FIG. 7, the left side being a mirror image thereof;
FIG. 10 is a rear elevation view of FIG. 7;
FIG. 11 is atop plan view of FIG. 7; and,
FIG. 12 is a bottom view of FIG. 7.
The details shown in broken lines form no part of the claimed design.