Portable water bottle cap

FIG. 1 is a left, front, top perspective view of the portable water bottle cap showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

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

FIG. 7 is a bottom plan view thereof.

The attached Appendices include reference views relating to the present design showing the portable water bottle cap in a state of use, showing a state in which a filter is received in the cap body and the filter case of the present design, and showing a state in which the present design is mounted to a portable water bottle.