Air treatment system filter

FIG. 1 is a front perspective view of the air treatment system filter of the new design;

FIG. 2 is a front elevational view, the back side being a mirror image thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is an enlarged portion of the air treatment system filter of FIG. 1 .

FIGS. 1-2 and 7 show features of the air treatment system filter in phantom lines. These features are shown for environmental purposes and do not form any part of the claimed design. Further, the phantom lines immediately adjacent the solid-line portions of the design form the boundary of the design, with the phantom lines forming no part of the claimed design.