I claim the ornamental design for a baluster spacer, as shown and described.
FIG. 1 is a perspective view of the baluster spacer showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation 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;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view showing the baluster spacer in an environment of use.
The broken lines in FIGS. 1-8 depicting a pan head screw, hex nut, and through-hole represent portions of the article which form no part of the claim. The broken lines in FIG. 8 depicting a deck baluster represent environmental structure and form no part of the claimed design.