FIG. 1 is a left perspective view of a shock absorber for power tool showing the new design. FIG. 2 is a right perspective view thereof. FIG. 3 is a rear view thereof. FIG. 4 is a right side view thereof. FIG. 5 is a left side view thereof. FIG. 6 is a top view thereof; and, FIG. 7 is a bottom view thereof. The broken lines that define the bounds of the claimed design form no part thereof.