FIG. 1 is a front view of a helmet showing my new design;
FIG. 2 is a rear view thereof;
FIG. 3 is a left-side view thereof;
FIG. 4 is a right-side view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a front perspective view thereof;
FIG. 8 is an enlargement of the encircled portion 8 in FIG. 1;
FIG. 9 is an enlargement of the encircled portion 9 in FIG. 1;
FIG. 10 is an enlargement of the encircled portion 10 in FIG. 2;
FIG. 11 is an enlargement of the encircled portion 11 in FIG. 2;
FIG. 12 is an enlargement of the encircled portion 12 in FIG. 2;
FIG. 13 is an enlargement of the encircled portion 13 in FIG. 5;
FIG. 14 is an enlargement of the encircled portion 14 in FIG. 5;
FIG. 15 is an enlargement of the encircled portion 15 in FIG. 6;
FIG. 16 is an enlargement of the encircled portion 16 in FIG. 6;
FIG. 17 is an enlargement of the encircled portion 17 in FIG. 7; and,
FIG. 18 is an enlargement of the encircled portion 18 in FIG. 7.
The broken lines in the figures depict portions of the helmet which form no part of the claimed design.
The dot-dot-dash broken lines encircling portions of the claimed design that are shown in enlargements form no part of the claimed design.