FIG. 1 is a top, front, right side perspective view of an air filter showing my new design;
FIG. 2 is an enlarged depiction of the left portion of FIG. 1;
FIG. 3 is an enlarged depiction of the right portion of FIG. 1;
FIG. 4 is a front elevation view thereof;
FIG. 5 is an enlarged depiction of the left portion of FIG. 4;
FIG. 6 is a back elevation view thereof;
FIG. 7 is an enlarged depiction of the right portion of FIG. 6;
FIG. 8 is a right side elevation view thereof;
FIG. 9 is a left side elevation view thereof;
FIG. 10 is a top, back, left side perspective view thereof;
FIG. 11 is an enlarged depiction of the right portion of FIG. 10;
FIG. 12 is a top, back, right side perspective view thereof;
FIG. 13 is an enlarged depiction of the left portion of FIG. 12;
FIG. 14 is a top, front, left side perspective view thereof;
FIG. 15 is an enlarged depiction of the left portion of FIG. 14;
FIG. 16 is a bottom, back, left side perspective view thereof;
FIG. 17 is an enlarged depiction of the right portion of FIG. 16;
FIG. 18 is a bottom, back, right side perspective view thereof;
FIG. 19 is an enlarged depiction of the left portion of FIG. 18;
FIG. 20 is a bottom, front, left side perspective view thereof;
FIG. 21 is an enlarged depiction of the left portion of FIG. 20;
FIG. 22 is a bottom, front, right side perspective view thereof; and,
FIG. 23 is an enlarged depiction of the right side of FIG. 22.
The broken line showing of various features of the air filter form no part of the claimed design.