The ornamental design for an implant tool, as shown and described.
FIG. 1 is a front, top, right perspective view of an implant tool, showing the new design;
FIG. 2 is a rear, bottom, left perspective view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines of uneven length shown in the drawings illustrate the boundary of the claimed design and form no part thereof. The broken lines of even length shown in the drawings illustrate portions of the implant tool that form no part of the claimed design.