Base for Storage Box

FIG. 1 is a top front perspective view of a base for storage box showing my new design;

FIG. 2 is a front view thereof and the rear view being a mirror image;

FIG. 3 is a right side view thereof and the left side view being a mirror image;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a bottom rear perspective view thereof.

The dashed broken lines in the figures show portions of the base for storage box that form no part of the claimed design.