Duffel bag

FIG. 1 is a top, front, right perspective view of a duffel bag showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines form no part of the claimed design. The vertical dashed lines represent unclaimed subject matter and form no part of the claimed design.