FIG. 1 is a perspective view of a boot warmer showing our new design in use;

FIG. 2 is a top plan view;

FIG. 3 is a first side elevational view;

FIG. 4 is a bottom plan view;

FIG. 5 is a second side elevational view;

FIG. 6 is a left side elevational view; and,

FIG. 7 is a right side elevational view.

The broken line showing of a boot in FIG. 1 is for illustrative purposes only and forms no part of the claimed design.