The ornamental design for a base, as shown and described.
FIG. 1 is a top-front-right perspective view of a base showing our new design;
FIG. 2 is a top-right-back perspective view thereof;
FIG. 3 is a bottom-left perspective view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a back view thereof;
FIG. 6 is a right-side view thereof;
FIG. 7 is a left-side view thereof;
FIG. 8 is a top view thereof;
FIG. 9 is a bottom view thereof;
FIG. 10 is a top-right-back perspective thereof with a handle removed; and,
FIG. 11 is a right-side view thereof with the handle removed.
The broken lines in FIGS. 1-9 depict portions of the base and environmental structures in the form of the handle and tubing that form no part of the claimed design.
The broken lines in FIGS. 10-11 depict portions of the base that form no part of the claimed design.