We claim the ornamental design for an air filter element, as shown and described.
FIG. 1 is a top front perspective view of an air filter showing our new design, the top rear perspective view is identical;
FIG. 2 is a front elevational view thereof, the rear elevational view is identical;
FIG. 3 is a left side elevational view thereof, the right side elevational view is identical;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a bottom rear perspective view thereof, the bottom front perspective view is identical to FIG. 6;
FIG. 7 is an enlarged view of the circled region “FIG. 7” of FIG. 6, showing an enlarged view of the oblong protruding portion;
FIG. 8 is an enlarged view of the circled region “FIG. 8” of FIG. 2;
FIG. 9 is an enlarged view of the circled region “FIG. 9” of FIG. 3; and,
FIG. 10 is an enlarged view of the circled region “FIG. 10” of FIG. 5.
The dash dot lines immediately adjacent to the claimed areas in FIGS. 5 and 10 represent the boundaries of the claimed design. The dashed lines in the figures illustrate the portions of the design that form no part of the claimed design. None of the broken lines form any part of the claimed design.