The ornamental design for a diffuser, as shown and described.
FIG. 1 is a perspective view of a diffuser of the present invention;
FIG. 2 is a perspective view thereof from a different vantage point; and,
FIG. 3 is a top plan view thereof.
In FIG. 1, the rear of the vanes below the full line disclosure of the upper surface is disclaimed. In FIG. 2, the portions of the vanes below the full line disclosure of the sloped face of the vanes and the rear of the vanes below the full line disclosure of the upper surface are disclaimed.
A bottom plan view and side elevation views have been omitted as they do not form a portion of the claimed design. The evenly spaced broken lines shown in the drawings are directed to environment, are for informational purposes only, and form no part of the claimed design. The long and short broken lines are boundary lines which define the bounds of the claimed design. These boundaries do not exist in reality in the article embodying the design. It is understood that the claimed design extends to these boundaries but does not include the boundaries.