I claim the ornamental design for a portable power product, as shown and described.
FIG. 1 is a top, front, left perspective view of a portable power product showing my new design;
FIG. 2 is a left side elevation view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a top, rear, right perspective view thereof, in an open position.
The ornamental design which is claimed is shown in solid lines in the drawings. The broken lines formed by dashes show unclaimed subject matter and form no part of the claimed design.