FIG. 1 is a bottom, front, left side perspective view of a diffuser showing a first embodiment of my new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a front elevational view thereof;
FIG. 7 is a rear elevational view thereof;
FIG. 8 is a bottom, front, left side perspective view showing a second embodiment thereof;
FIG. 9 is a bottom plan view of FIG. 8;
FIG. 10 is a top plan view of FIG. 8;
FIG. 11 is a left side elevational view of FIG. 8;
FIG. 12 is a right side elevational view of FIG. 8;
FIG. 13 is a front elevational view of FIG. 8;
FIG. 14 is a rear elevational view of FIG. 8;
FIG. 15 is a bottom, front, left side perspective view showing a third embodiment thereof;
FIG. 16 is a bottom plan view of FIG. 15;
FIG. 17 is a top plan view of FIG. 15;
FIG. 18 is a left side elevational view of FIG. 15;
FIG. 19 is a right side elevational view of FIG. 15;
FIG. 20 is a front elevational view of FIG. 15; and,
FIG. 21 is a rear elevational view of FIG. 15.
The dashed broken lines of the figures represent unclaimed portions of the diffuser and form no part of the claimed design. The dash-dot broken lines of FIGS. 15-17 and 20-21 define boundaries of the claimed design, and form no part of the claimed design. The pairs of adjacent wavy break lines of FIGS. 1-3, 6-7, 15-17, and 20-21 form no part of the claimed design, and indicate that the appearance of any portion of the article between the break lines forms no part of the claimed design.