The ornamental design for a sauna apparatus for knee, as shown and described.
FIG. 1 is a bottom view of a sauna apparatus for knee showing our new design;
FIG. 2 is a front view of the sauna apparatus for knee;
FIG. 3 is a left side view of the sauna apparatus for knee;
FIG. 4 is a perspective view of the sauna apparatus for knee;
FIG. 5 is a rear view of the sauna apparatus for knee;
FIG. 6 is a perspective view of the sauna apparatus for knee, with the door open;
FIG. 7 is a right side view of the sauna apparatus for knee; and,
FIG. 8 is a top view of the sauna apparatus for knee.
The dash dot lines immediately adjacent to the claimed areas in the views 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.