The ornamental design for a counterweight for a fork lift truck, as shown and described.
FIG. 1 is a perspective view of a counterweight for a fork lift truck as seen from the top, rear and left side showing our new design and the environment of a fork lift truck which uses the counterweight;
FIG. 2 is a perspective view thereof as seen from the top, rear and left side shown on an enlarged scale;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken line showings in the figures are for illustrative purposes only and form no part of the claimed design.