The ornamental design for a pet double bowl, as shown and described.
FIG. 1 is a top perspective view of a pet double bowl, showing my design.
FIG. 2 is a bottom perspective view thereof.
FIG. 3 is a front elevation view of the pet double bowl of FIG. 1, a rear elevation view of the pet double bowl of FIG. 1 being symmetrical to the front elevation view of the pet double bowl of FIG. 1.
FIG. 4 is a left side elevation view of the pet double bowl of FIG. 1, a right side elevation view of the pet double bowl of FIG. 1 being symmetrical to the left side elevation view of the pet double bowl of FIG. 1.
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom plan view thereof.
The broken lines in the drawings depict environmental structure and boundaries and form no part of the claimed design.